[AccessD] SQL Server - Query non-updateable

I have a selection query for a bound form.  If I just do a select xyz from tblInmate it works of 
course.  I want to select a subset of inmates that reflect those that I work with (specific camps).

I have a tblVolunteerCamps (the camps that a volunteer works with) and I built a stored procedure 
out in SQL Server that selects the IDs of inmates at those camps.  I feed the SP the volunteer ID 
and back comes the campIDs and the inmateIDs in those camps.

I had read (on this list) that if I used IN (SELECT ID from QueryXYZ) in the where clause it would 
allow the query to be editable but doing so is turning my query into a non-updatable query.

SELECT TblInmate.* from tblInmate
WHERE (INM_Active <> 0) AND
(INM_Location IN (SELECT CMP_LOCCODE FROM qspVolCampIDs))

If I remove the IN clause, the query is updateable.

I really need to filter to just the camps the volunteer works with and I am wondering how to 
accomplish this.  In the past I would try to JOIN the main query to the selection filter and that 
caused non-updateable.  I was told to use the IN(SELECT) which has worked in most cases in the past.

Any clue why not now and how to go about filtering and keeping it updateable?

-- 
John W. Colby
www.ColbyConsulting.com