After fighting a few days, and with the kind help of Nokia people:
Just do what manuals say (that is: use some COMX in local services and client applications: you find it in "advanced configuration", :
My bluetooth sites/bluetooth/advance configurations/local services
You have to select two different COMs here! you need both!
Then, select in "mrouter" this two defined COMs, ad close the window.
AND NOW THE SPECIAL TRICK:
Just shut completely down your NOKIA 6600. Restart it (this is VITAL: it collapses with all youre past trials!
Then return to
My bluetooth sites/bluetooth/search for units
click on your detected NOKIA, right mouse/detect services
clich on right mouse/connect toserial Bluetooth...watch mrouter icon changes!
Accept in the phone
dont believe an error message that apprs in the PC
wait for a following mess. in PC inviting you to accept the mobile phone...ando VOILA! your connection is there!
Each new connection, you may have to reset the NOKIA...
Be happy, be lucky, be honest!
JAvier