A frequently Asked Question concerning the use of Notifications is:Where can I set up QM_REPLY?
and How do I replace QM_REPLY with my own form?
Well actually the issue in this case is the fact that QM_REPLY is hardcoded in the QM06 functional group, this means that you can either modify the standard top include in the QM06 Functional group (Not recommended by SAP) or you can check the following:
The solution is to copy the original of function group QM06 (to e.g. ZQM06). In this new function group you can adjust the 'top-include' according to your specifications. Generally these modules were designed as examples for you use as copy models.
Please read the documentation in customizing too:
>Additional Notification Functions
> Define Action Box
I hope that this solution is usefull