Check out a similar post: http://www.sqlservercentral.com/Forums/Topic600005-148-1.aspx#bm613484

I haven't done the deployment into SQL Server (using filesystem instead) but sounds like you could benefit from using a Proxy Account & Credentials. See the link in the above post regarding a how-to video by Brian Knight at http://www.JumpStartTV.com - lots of SQL videos there, not just SSIS.

Here's a link to a video about creating a Proxy Account: http://jumpstarttv.com/creating-a-proxy-account_147.aspx?searchid=8597

Hope this helps..