You need to make sure your stored procedure returns the variable that you are going to join with. 

Here is an example:

SELECT a.propid, b.EconomicZone_Code, a.MTQUST_Combo, a.Model_Code, a.Quality_Code, a.Structure_Code
         FROM Table1 a
         LEFT OUTER JOIN Procedure1(a.propid) b on b.propid = a.propid