Killing MTS object

We are developing a VB application which is using MTS and activeX exe.The
architecture of the application is as below :
Front end(GUI) will call activeX exe. ActiveX exe will call to MTS
object (dlls in MTS).
when we stop the application from frontend (setting activex object to
nothing).will call to class_terminate of exe, but exe is not able to close/kill
the reference of MTS object.
Functionality required is when we remove reference of Acivex exe from GUI
,application should also remove referece of MTS object. immediately