Stored Procedure

How do you execute a stored proc against a sql sever to authenticate a user. What do you do with the response to either accept or reject the user? We are trying to authenticate the user by returning a 1 for yes or 0 for no. The stored proc is executed by the update control but the User Password is not being added, its only adding the User-name and leaving the Userpassword field blank. Tmp-String-0 := "%{sql:EXEC [IsUserAuthenticated] ('%{User-Name}','%{User-Password}'" } if (Tmp-String-0 =~ /1/) update control { &Auth-Type := Accept }