Hello there

Iím trying to add a new Integrated Zimlet in the New Message dropdown list menu. When I do a click in the arrow I see options like Message, Contact, Contact Group, Appointment, task, etc. and I need to add a new element under the Message Item.
I canít figure it out how to do this since Iím new Zimlet developer and I donít know how to access this toolbarÖ
I will appreciate some help.