[gtkmm] Creating GTK+ widgets with GTKmm? Is this possible?

[Juan Linietsky <coding reduz com ar>]

Hello! I have to say I love gtkmm, and use it in all my projects.
But i'm asked to write some specific widgets that can be used from
regular
GTK+. I dont know how to write widgets in plain gtk, but do you people
think it's possible to create them in gtkmm and then using a normal
C++ -> C
wrapping have a common GTK widget? I'd be glad to hear if this has
been done before, 
or maybe my idea is too crazy. :)

Juan Linietsky