Ok following steps needed to be taken to get my bluetooth mouse working:

emerge bluez
/etc/init.d/bluetooth start
hcitool scan (find your mac of the mouse = macM)
hciconfig (remember mac of the bluetooth dongle = macD)
vim /var/lib/bluetooth/<macD>/pincodes

add <macM> <pincode> (=0000 for mighty mouse)

/etc/init.d/bluetooth restart

unpack the /usr/portage/distfiles/bluez-4.x.tgz somewhere and go to the test folder

./simple-agent hci0 <macM>

enter pincode

./test-device list (remember path =mouseP) dbus-send --system --dest=org.bluez --print-reply <mouseP> org.bluez.Input.Connect

example

dbus-send --system --dest=org.bluez --print-reply /org/bluez/4924/hci0/dev_00_1F_F3_DE_84_47 org.bluez.Input.Connect

Hopefully it will connect whenever I need it worst case I will have to reexecute the dbus-send

greetings!