Adding an item to a task or stick which references to an external app

Hello,

perhaps someone could give me some hints to solve the following problem:

I want to create task, calendar entries, notes and mails from my
programm. This could be easly done via Extended Mapi. The objects which
I create should reference data in my program, a database-application.

A task (for exmaple) could look like that:
"This is a task for you. Click in the attached document or link to get
details".

If the user clicks on the document, link or something else which solves
my problem my program should be called to serve the data from the
database and display it in a window.
The second extension would be that if the user finished the task in
outlook my program should notice that to set a flag a the database.

I tried a pluggable protocol hanlder already in hope that Outlook marks
myhttp://... as link to if the protocol is registered but Outlook
doesn't.

Any other suggestions?

Thanks

Stefan Westner