Did anybody manage to write a scriptable plugin for linux ?

I all
As stated in the subject , i want to write a scriptable plugin for linux.
Like all beginners in that matter, i pulled down the mozilla source tree
edited the allmakefiles.sh to add a line telling configure to write a
makefile for mozilla-1.3/modules/plugin/tools/sdk/samples/scriptable/unix
It did it.
I build the whole tree with gmake and whatched tv for a while waiting for
the process to finish..

cd to the scriptable plugin directory and tried to build the stuff
as it wasn't already built (contrarily to the simple plugin).
But then came out errors (npapi.h and nupp.h headers not found, plus
no rules to make libplugingate_s.a)
Fixed it creating an "../../../include" directory with npapi.h and nupp.h
inside and replacing this line:

SHARED_LIBRARY_LIBS = $(DIST)/lib/libplugingate_s.$(LIB_SUFFIX)

with:
SHARED_LIBRARY_LIBS = ../../common/libplugingate_s.$(LIB_SUFFIX)

OK now i can compile the beast....

Placed the *.xpt files into the /usr/lib/mozilla-1.3/components
directory.
Put the libnpSDKscriptable.so file into the plugin directory:
cp libnpSDKscriptable.so /usr/lib/mozilla-1-3/plugins


backed up the xpti.dat file somewhere else and have it regenerated using 
/usr/lib/mozilla-1.3/regxpcom

OK i can see the new lines in the new xpti.dat file...

126,npSDKscriptable.xpt,0,168,1053302295000
127,nsIScriptablePluginSample.xpt,0,168,1053302298000

The plugin is registered since in can see it in about:plugins
It draws the nice little black rectangle inside the grey window under the
text...

But nothing happens when i click any of the two buttons under this
rectangle... The big void...

So several questions:


Has anybody been able to build a scriptable plugin under and for linux, but
any windows feedback could be helpful as well, with 
this sdk or is the old sdk ( unix-sdk-3.0b5.tar.Z) the one should 
use in the end (as i read in ONE post)?
see: http://groups.google.fr/groups?q=plugin+mozilla+AFAIK&start=
10&hl=fr&lr=&ie=UTF-8&selm=aprsml%24q4v1%40ripley.netscape.com&rnum=20

Why do i have to fiddle with the Makefile to have it finally built or is it
that the sdk isn't finished yet or will it never be ?

Is there somewhere a working sample of scriptable plugin code (with methods
callable from javascript)  that works on linux (plus windows AND mac)?

As i think it's a xpcom related pb, where should i look to have 
a thorough, clear, concise view about how xpcom works?

Thanks
Rico