Extend finance modules (tenders, invoices,...) to link to activity expense

Hi, all.

Sometimes the procurement process of an item take so much time that it needs to be an activity.
I would like to have some finance module like, Call for tenders, Orders to provider, Provider invoices, etc., to be able to link to activity expense (in treatment tab). Currently only project expense can be linked. And automatically generate activity expense feature would be nice.

Thanks!