Startup engines on PMDG with pmSystems

The PMDG 737ng is the best product of its type currently on the market.
Unfortunately all of the sofisticated panel stuff is to put out of service
when using this plane with PM and pmSystes in particular. However, the
patch
of Bob Scott does not resolve the strange problem I discovered. I can't
succeed in starting the engines of an PMDG with pmSystems. As mentioned in
the doc's I replaced the whole PMDG-panel with the default B737-400 panel
but ones the N2 has reached more then 20% and the fuel cut-off levers are
opened, the RPM of the engine drops immediately so the engines will never
start. That same plane is to be started normally when pmSystems is not on
line. Evenso no problem with pmSystems and the default B737-400. I can
remember the demo-movie of an engine startup made by Jonathan Richardson,
showing the use of the PMDG737, so there must be something not documented
in
order to get to a normal engine startup with a patched PMDG7373 with
default
MSFS-panel. Has somebody any idea what could be escaped to my attention?

Jan Moons