Got it - using some of the hints earlier in the thread:

[font="Courier New"]ALTER PROCEDURE SR_numinput

@SR_number VARCHAR(20),

@customer VARCHAR(50) OUTPUT,

@project VARCHAR(20) OUTPUT

AS

BEGIN

declare @query NVARCHAR(500);

declare @parm NVARCHAR(500);

set @parm = N'@cust VARCHAR(50) OUTPUT,

@proj VARCHAR(50) OUTPUT';

set @query =

'select @cust = NAME, @proj = PROJ_NUM FROM

openquery(AtlasTest,

''Select P.NAME,P.PROJ_NUM from SXXX.S_SRV_REQ S, SXXX.S_PROJ P

where p.row_id=s.proj_id and s.sr_num='''''+@SR_Number + ''''' '')';

select @query;

execute sp_executesql @query,

@parm,

@Cust = @customer OUTPUT,

@Proj = @project OUTPUT;

select @customer as oCustomer, @project as oProject;

END[/font]

Build up the select string with the input values included.

Then use sp_executesql with defining the OUTPUT variables required, and map them to the procedure/trigger variables in the call.

Kind of ugly, but there it is.