You can use SPT parameters

liID = 12345
lnRetVal = SQLEXEC(lnCon, "EXECUTE PROCEDURE DelUStock(?liID);")
...

The 'returning_values' part is optional and I'm not sure how to correctly specify it for SQLEXEC().

>
>>Whatever you specify as 2nd parameter in SQLEXEC() is passed to a backend for excution w/o changes. IOW, you call SP the same way as you would in the backend.
>
>I have checked out on the FireBird forum and it is supposed to be called as follows:
>
>EXECUTE PROCEDURE DelUStock(OLD.iID)
>returning_values(:returnvalue);
>