I do have to warn you with this. In the time that the sony xperia X1 came out, I bought one.

While this phone does not officially support rSAP, it's 'brother' the HTC Touch HD did. Hardware wise they where exactly the same and using xda-developers there was enough, well tuned, well optimized firmware to around.

Up until this date, I know of no-one whom has a HTC device with Windows mobile that can use their rSAP implementation successfully, all of the time. With some it works, with some it works half of the time and with some, it won't ever work.

With the X1 I had the experience that with 5 different sim cards, 2 would work, one would half of the time and 2 would never ever work..... way way to vague behavior to consider workable and off course, my own sim would not work. The only trend I could discover with this is that newer SIM cards (with more sim memory) had problems with the rSAP implementation of HTC.

Now it's been a few months that I tried it, but I would consider this VERY carefully before everything buying a HTC phone with the idea in mind that you can use rSAP.

Even the Samsung i8910 (which I bought after the X1) which runs Symbian s60v5, like the N97 for instance give me so much trouble with it (sometimes it worked, sometimes it didn't, but worst of all, randomly the receiver would not come back on after leaving the car!).... unworkable. Samsung refused to fix it, while I had had similar problems in the past with nokia, which they always fixed after a few firmware releases.

So back to nokia for me, and to the N900. I'd rather have it not work AT ALL, the half or unreliably... So now I will use two phones for as long as it's needed.... the carkit wil not work with anything else then nokia's, since it was made by nokia. Had I known on forehand.... I would not have bought it... and would have sprung for the fiscon carkit unit, half the price....