Use a passthrough query to exec your stored procedure which returns the required records, and use the (passthrough) queryname as the rowsource for your listbox. Make sure that the RowSourceType property is set to Table/Query.
To get this working, set up and test the passthrough query first. Then when its working, 'connect' it to the form via the listbox.
You get to Passthrough queries via the Query, SQL Specific, Passthrough options of the Query Design window. Enter the required sql/SP invokation in the window, and ensure that the query properties (View, Properties option) are set appropriately (in particular, the ODBC connection string, ReturnRecords set to Yes, you may need to set the ODBC Timeout to zero.
Hope this approach sorts it out,
Steve Lewy
Solutions Developer
steve@lewycomputing.com.au
(dont cut corners or you'll go round in circles)