Full Face masks for higher pressures?

Hi everyone,
I was just issued a new machine (BiPAP ST) with new pressure settings 20/16 with a back up rate of 8. My old pressure settings were 17/13 with no backup rate and it tolerated the pressure just fine. Well with my new pressure settings my Mirage liberty leaks like a sieve. I am going to the DME tomorrow to get it looked at, and was wondering if anyone could suggest a full face mask that may tolerate higher pressure settings a little more effectively. I have tried loosening the mask, and tightening it to the point to where it was almost unbearable and no luck, and Im at the point to where Im going to try a nasal mask and a chin strap and learn to live with it. Thanks in advance for any advice you may be able to offer!

Resmed Mirage Quattro is still one of the best....

Have you considered the new SleepWeaver full face mask? According to their website: "SleepWeaver Anew has been tested and approved for use between 4-30cm H20 on CPAP, Bi-Level and Auto-titrating PAP systems." Here's a newly posted video on this mask: http://www.youtube.com/watch?v=xWPtpuCrFow

I've been doing very well with the Sleepweaver Advance nasal mask, but I am considering one of these as a backup as I have a top pressure of 21, which is above the pressure rating for the Advance mask.