Hey Nikos,
I went through all that heat shit with my 999R last summer.
Check out this thread:
999R 04 models - power and heat?
Read page 2 as well.
If you fancy some German written input, go to my blog and translate with babelfish or something similar:
Powerwheelie Motorrad Rennsport Weblog
Next to that, here´s an image of the thermostate assembly, which demontech and Ducati23 are talking about
: