Adding shapes to dia

[myken <myken iae nl>]

Hello, I'm new to the list and I have not found an answer to my question
using google, sorry. So here it comes.

Is there a detailed tutorial on how to add sheets/shapes to dia?
This is my problem:
I like to add/change a sheet to the dia core.
So I copied the SADT.sheet.in to mySADT.sheet.in and the SADT sub-dir to
mySADT. 
Changed the file names "box.c" to "mybox.c"
Changed the references to the SADT shapes into mySADT shapes (mySADT -
fbox).
Changed the library reference (libmysadt_objects.la)
Changed the objects/Makefile.am
Changed the sheets/Makefile.am
Added "objects/mySADT/makefile to AC_OUTPUT in configure.in

Now if I run ./autogen.sh, ./configure and make all is fine (no errors).
If I start Dia (./app/run_dia.sh ) Dia runs as expected. I can even see
me sheet (mySADT) BUT there are no shapes visible. I can not select
anything.

What am I missing?

Any help is greatly appreciated.

Thanks, Robert.