C++ & KDE4 Plasmoid

I asked the following question to the panel-devel mailing list, but
without success. Maybe one of you can help me out.
I have build a plasmoid and an engine. Both communicate with each
other, so I tried to let the engine create dynamic data, and the
plasmoid had to ask the engine for new data. So this should be the

dataEngine("test01engine")->connectSource("test01applet", this, 5000,

I thought this should call test01engine (sourceRequested()) every 5
second, according to this documentation:
libplasma: Plasma::DataEngine Class Reference
but nothing happens. Well, nothing, the applet calls test01engine when
it starts, but just that one time only. What am I doing wrong?
The source for the plasmoid:
The source for the engine:

Thanks in advance!