James,
Try declaring an additional parameter as an OUTPUT parameter, ie:

CREATE PROC sp_getkey @tablename varchar(50), @returnkey integer OUTPUT AS.....

Set the @returnkey parameter in your stored procedure and check it AFTER calling the execute method to see what value was returned.

.Execute()
lnReturnKey = .Parameters('@returnkey').Value

Typically, creating a recordset that only contains one value is a lot of overhead and should be avoided if you can return a parameter instead.

Hope this helps.
Kurt