Business workflow without SAP users

[Márton Zsolt]

Hi all,
We are in ECC 6.0.
I have to solve a problem to one of our customer. They need a fully developed workflow for releasing WBS elements. (changing user statuses)
The status changes are controled by workflow, but I need to send the tasks to MS Exchange for non SAP users.
Is this possible to send a decision task to a mail client and to receive the result from those people? 

Thanks in advance
Zsolt