6 ohm speakers with Onkyo HT-R520?

I'm a bit of newb when it comes to speakers and I'm trying to fully understand the impact of speaker impedence and what I can and can't do with my receiver.


I recently bought the Onkyo 770 HTIB that comes with the R520 receiver. In the manual, it lists the specs below, specifically mentioning "Speaker impedance: 6ohm~".


Specifications

Amplifier Section


Power output:

All channels: 130 W (8ohm, 20 Hz-20 kHz, FTC)

Dynamic power: 2 x 260 W (3ohm, front)

2 x 200 W (4ohm, front)

2 x 150 W (8ohm, front)

THD (total harmonic distortion): 0.08% (rated power)

Damping factor: 60 (front, 1kHz,8ohm)

Speaker impedance: 6ohm~


I know the speakers that came with the 770 are all 8 ohm speakers, but I have a pair of older/nicer front speakers that are rated at 6 ohm. My question is, can I hook up these 6 ohm speakers as the "B" speakers, or can I replace the fronts that came with the 770 and use these 6 ohm speakers as my "A" fronts instead? Or would it be too much for this receiver to handle? (would I run the risk of damaging the receiver?) Also, if I do hook them up as the B speakers, would I be able to run the A+B speakers together at the same time?


Thanks in advance!