With a standard Access query you can embed references to a field on an Access form (ie: Forms!FormName!ControlName), but Pass Through queries are sent to the SQL server as written - Access does not attempt to parse the SQL statement first, only allowing you to filter the results.

The only options I have seen/used to do this are the Filter parameters described previously, or through VBA code to manipulate the SQL Pass Through query before it is sent to the SQL server.

The VBA to do this is quite simple (just a few lines) so if anyone wants a sample I can post one.