Perhaps it's a shot in the dark and I don't know anything about Sharepoint lists but, if you can write a stored proc that accesses the XML in a SQL query (via OPENXML or some other method) you can pull the column names out as shown below. For the example I'm assigning the XML as a variable for demo purposes.

-- Demo XML (you would access the sp list xml differently

DEClARE @SPList XML =

'<RSSharePointList xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">

<ListName>AM_Headings</ListName>

<ViewFields>

<FieldRef Name="Title" />

<FieldRef Name="FLDTYPE" />

<FieldRef Name="ACCEL_DEPR" />

<FieldRef Name="ACCOUNT" />

<FieldRef Name="ACCOUNT_AD" />

<FieldRef Name="ACCOUNT_FA" />

<FieldRef Name="BEGINNING_COST" />

<FieldRef Name="ENDING_COST" />

<FieldRef Name="GPBR" />

<FieldRef Name="PRIOR" />

<FieldRef Name="CURRENT" />

<FieldRef Name="TICKET_NUMBER" />

<FieldRef Name="FIRST_6" />

<FieldRef Name="LAST_4" />

<FieldRef Name="GL_AMOUNT" />

<FieldRef Name="BANK_AMOUNT" />

<FieldRef Name="AUTHORIZATION_NUMBER" />

<FieldRef Name="BRANCH_NAME" />

<FieldRef Name="PAYMENT_DATE" />

<FieldRef Name="PHYSICAL_LOCATION " />

<FieldRef Name="VOUCHER_STYLE" />''''new

<FieldRef Name="VENDOR_LOCATION" /> ''''new

<FieldRef Name="INVOICE_TOTAL" /> ''''new

<FieldRef Name="MONETARY_AMOUNT" /> ''''new

<FieldRef Name="LinkTitleNoMenu" />

<FieldRef Name="LinkTitle" />

<FieldRef Name="ID" />

<FieldRef Name="ContentType" />

<FieldRef Name="Modified" />

<FieldRef Name="Created" />

<FieldRef Name="Author" />

<FieldRef Name="Editor" />

<FieldRef Name="_UIVersionString" />

<FieldRef Name="Attachments" />

<FieldRef Name="Edit" />

<FieldRef Name="DocIcon" />

</ViewFields>

<Query>

<Where>

<And>

<Eq>

<FieldRef Name="Title" />

<Value Type="Text">

<Parameter Name="LANGUAGE" />

</Value>

</Eq>

<Eq>

<FieldRef Name="FLDTYPE" />

<Value Type="Text">LONGDESCR</Value>

</Eq>

</And>

</Where>

</Query>

</RSSharePointList>';

-- query to return the column heading values

SELECT

col1 = v.value('(ViewFields/FieldRef[01]/@Name)[1]','varchar(50)'),

col2 = v.value('(ViewFields/FieldRef[02]/@Name)[1]','varchar(50)'),

col3 = v.value('(ViewFields/FieldRef[03]/@Name)[1]','varchar(50)'),

col4 = v.value('(ViewFields/FieldRef[04]/@Name)[1]','varchar(50)'),

col5 = v.value('(ViewFields/FieldRef[05]/@Name)[1]','varchar(50)'),

col6 = v.value('(ViewFields/FieldRef[06]/@Name)[1]','varchar(50)'),

col7 = v.value('(ViewFields/FieldRef[07]/@Name)[1]','varchar(50)'),

col8 = v.value('(ViewFields/FieldRef[08]/@Name)[1]','varchar(50)'),

col9 = v.value('(ViewFields/FieldRef[09]/@Name)[1]','varchar(50)'),

col10 = v.value('(ViewFields/FieldRef[10]/@Name)[1]','varchar(50)'),

col11 = v.value('(ViewFields/FieldRef[11]/@Name)[1]','varchar(50)'),

col12 = v.value('(ViewFields/FieldRef[12]/@Name)[1]','varchar(50)'),

col13 = v.value('(ViewFields/FieldRef[13]/@Name)[1]','varchar(50)'),

col14 = v.value('(ViewFields/FieldRef[14]/@Name)[1]','varchar(50)'),

col15 = v.value('(ViewFields/FieldRef[15]/@Name)[1]','varchar(50)'),

col16 = v.value('(ViewFields/FieldRef[16]/@Name)[1]','varchar(50)'),

col17 = v.value('(ViewFields/FieldRef[17]/@Name)[1]','varchar(50)'),

col18 = v.value('(ViewFields/FieldRef[18]/@Name)[1]','varchar(50)'),

col19 = v.value('(ViewFields/FieldRef[19]/@Name)[1]','varchar(50)'),

col20 = v.value('(ViewFields/FieldRef[20]/@Name)[1]','varchar(50)'),

col21 = v.value('(ViewFields/FieldRef[21]/@Name)[1]','varchar(50)'),

col22 = v.value('(ViewFields/FieldRef[22]/@Name)[1]','varchar(50)'),

col23 = v.value('(ViewFields/FieldRef[23]/@Name)[1]','varchar(50)'),

col24 = v.value('(ViewFields/FieldRef[24]/@Name)[1]','varchar(50)'),

col25 = v.value('(ViewFields/FieldRef[25]/@Name)[1]','varchar(50)'),

col26 = v.value('(ViewFields/FieldRef[26]/@Name)[1]','varchar(50)'),

col27 = v.value('(ViewFields/FieldRef[27]/@Name)[1]','varchar(50)'),

col28 = v.value('(ViewFields/FieldRef[28]/@Name)[1]','varchar(50)'),

col29 = v.value('(ViewFields/FieldRef[29]/@Name)[1]','varchar(50)'),

col30 = v.value('(ViewFields/FieldRef[30]/@Name)[1]','varchar(50)'),

col31 = v.value('(ViewFields/FieldRef[31]/@Name)[1]','varchar(50)'),

col32 = v.value('(ViewFields/FieldRef[32]/@Name)[1]','varchar(50)'),

col33 = v.value('(ViewFields/FieldRef[33]/@Name)[1]','varchar(50)'),

col34 = v.value('(ViewFields/FieldRef[34]/@Name)[1]','varchar(50)'),

col35 = v.value('(ViewFields/FieldRef[35]/@Name)[1]','varchar(50)'),

col36 = v.value('(ViewFields/FieldRef[36]/@Name)[1]','varchar(50)')

FROM (VALUES (@SPList)) spList(x)

CROSS APPLY x.nodes('RSSharePointList') v(v);

Copy/paste/run this in a local SQL instance, you'll notice that it returns one row with each column name. If you can get that far you're home free. All you need to do then is turn that into a data set and, for the column heading value, use an expression that references the value of col1, col2, col3, etc....

Hope this helps, let me know if you have any followup questions or if this won't work at all.