Making wxSimpleHelpProvider more useful

wxSimpleHelpProvider seems to have the following two unfortunate properties

1) ShowHelp takes a wxWindowBase* which wxPython doesn't seem to know how to
generate from a wxWindow
2) ShowHelp can't be overridden (wxPython silently ignores any override
definition)

I was pondering making a wxPySimpleHelpProvider in the style of lots of
other classes, and using {DEC,IMP}_PYCALLBACK* macros to get the override
behaviour. My current problem is that wxHelpProvider doesn't inherit from
wxObject, which causes the following macro:

IMPLEMENT_DYNAMIC_CLASS(wxPySimpleHelpProvider, wxSimpleHelpProvider);

to fail on compliation with

src\msw\help.cpp(99) : error C2440: 'return' : cannot convert from 'class
wxPySimpleHelpProvider *' to 'class wxObject *'
        Types pointed to are unrelated; conversion requires
reinterpret_cast, C-style cast or function-style cast
error: command '"C:\Program Files\Microsoft Visual Studio\VC98\BIN\cl.exe"'
failed with exit status 2

Does the fact that wxHelpProvider is not a wxObject fatally sink this
approach?

Right now I'm thinking of just making ShowHelp take a wxWindow* and casting
- think that might work and would get me past problem 1) above, which is the
most serious for my application.

Any comments appreciated,

S.