Sending data to a stored procedure call

I am attempting to call a stored procedure in another database, the stored procedure accepts a xml file to process.
I can connect to the database and execute the stored procedure but am not sure how to send it the xml file. Actually the xml is not really xml or a file, but a xml tag type string, it is only 1024 characters containg info from the NAV database.
Here is the execute
sSQL:=STRSUBSTNO('EXEC Stx_from_nav_exchange_rate ''%1''', SoftraxXMLString);
adoRS := adoConnection.Execute(sSQL );

Can anyone lead me in the way to then send the string to the procedure?

Thanks