[Zope] Icons not set right after Subclassing

[VanL]

Hello,

I have a Folderish Class "GenericHost".

I then have some specializations of this host, declared as

SpecialHost(GenericHost):
    (Differences here)

SpecialHost2(GenericHost):
    (Differences)


I then declare them in __init__ as follows:

    context.registerClass(
        Hosts.SpecialHost,
        constructors = (Hosts.addSpecialHostForm, 
Hosts.manage_addSpecialHost),
        icon = 'icons/SpecialHost.gif'
        )
    context.registerClass(
        Hosts.SpecialHost2,
        constructors = (Hosts.addSpecialHost2Form, 
Hosts.manage_addSpecialHost2),
        icon = 'icons/SpecialHost2.gif'
        )

GenericHost is never registered.  However, the icon directive is 
ignored; they all get a plain folder icon.
When I do register GenericHost and give it its own icon, then everything 
then gets the GenericHost icon. Otherwise, everything works as expected.

I've tried the misc_ trick, but I can't get it to work.  Can anyone tell 
me what I'm doing wrong?  It seems like a waste to repeat all of the 
code just for the icons.

TIA,

VL