[Product-Developers] PloneArticle - MyProduct's proxy-field in portal_types but not listed in archetypes_tool

[SimO]

Hi guys,

CONTEXT: Plone 3.1.7 - PloneArticle 4.1.2 - MyProduct based on PA

I need an extra field in PA in order to manage images, attachments, 
links, MyObjects  directly in PA edit tabs,

so I created MyProduct which inherits from PA and I added 
MyProjInnerContentField to it.

MyProjInnerContentField has its class, its interface 
(IMyProjInnerContentField) and a proxy (MyProjInnerContentProxy) with 
its interface (IMyProjInnerContentProxy).

MyProduct is installed correctly and I can see 'MyProjInnerContentProxy' 
listed into portal_types BUT NOT in archetypes_tool,

which means that when I create my MyType and Plone try to save it the 
BaseInnerContent's method 'getInnerContentSchema' can't find it and 
raises the error "Inner content is not registered".

I assume that the registration is done after the declaration of the 
proxy's class trough "registerType(MyFieldInnerContentProxy)", am I wrong?

I searched in PloneArticle for something else that register the fields 
into archetypes_tool but ..nothing.

What am I missing?

TIA
SimO