Well it is possible that nothing you do will calm her down. The calm gentle touch you are doing is likely the best way perhaps starting slower and just touching her sides instead of actually handling her might help too. I also found that a bit of your scent from a bit of cloth (I just wore an old shirt around for a day and then cut it up) placed in the hides help to relax my flighty ones at least for spot cleaning, mine went from crazy hissing and posturing to just staying out of the way.