I used to grow all my roses (mostly hybrid teas but also some old garden types) in full sun in Phx. on the south side of the house! Now Im in LHC and its def. hotter here and BHC is prob even worse lol. I plan to put mine in full morn sun/afternoon shade here. I think they will do well and get enough sun to flower okay that way. I am also going to plant some tree roses in foam or wood type planters which are poor conductors of heat. Gonna set them on the porch on top of a round piece of cork or a potholder made of silicone (this will keep them from cooking on the hot cement)
I think you might be in a zone 10, like we are here. I'm not sure about the Austin roses, do they like cooler temps? If you put them in the ground you might want to run a drip line under some mulch with something like wood chips or pine needles (dont use rubber mulch it heats up too much and will cook the roots) Wood and pine needles stay cooler.
Hope someone else local can give you more tips!
~SJN

If I were you I would check to see if yo have a local Rose Club. I have heard that there is a new breed of roses on different root stock for our climate that is doing better here. It also depends were you buy the roses. You need top quatily. If can't get help were you are contact the PHX rose club.
Mickey