Just search for some settings for your 280x..I get 3650kh/s for x11 ,7950.
Glad it is working now

edit ah you are hashing x13..don't know what hashrate I get with x13..
1 more question, what if i want to add x15 in auto-switching too? what will be the value of "fx=x" for x15?
"pass" : "f0=0;f2=0;f3=4;f4=3;f5=0;f6=0;f7=0", (this pass is for x11 and x13 only)