@SQL Noob: Thanks for your reply.

I also did that:

Creating a DTS-Package and execute it within SSIS. SSIS DOES use ODBC, I can get my data, as long as no user is committed on the INformix-DB table. But that is no clean solution for me.

Actually, now I try to connect via Informix OLE DB driver. I´ll let you know when I come to a solution.