Monitor using FW 410

[Kap Zuul]

I'm using Live 5 with a FW 410 and had some Problems while monitoring my Last Gig. I used my headphones to monitor through headphones out 2, but sometimes the volume of the PA was louder than the phones. And: the PA sounded obviously totallly different than my phones mix.
Please suggest a better way to monitor with my equip
Thx