how to access 3g or H+ on an unlocked T-Mobile TP2

[burlcone]

I have used the Touch Pro2 for about 3 years and have been very satisfied with nearly everything with the phone. I have gone through three phones because of the power button failing, and as a workaround I've started to use the sliding keyboard as a way to turn on the phone and prolong the power button's life. The main issue I have now I that I bought this last time a chrome-backed phone from eBay which looked like a good deal, not especially cheap but it was said to be new and apparently is new, the phone time use indicator said it had been used 0 hours, 0 minutes when I got it.

However, the new phone is unlocked -- it's a HTC randed phone, not T-Mobile branded -- and it seems that I cant get a faster connection speed than EDGE, where I used to get connections of 1 mbps down and up regularly, as measured from the phone browsers and also from a laptop tethered to the phone. It seems that this is a common issue with unlocked phones in general. Any fix for this for the Touch Pro2 (TP2) on T-Mobile? Any way to lock the phone and enable 3G (and HSPA, if that's somehow locked/unlocked different) data? I am not sure but I think what needs to be changed is in the bootloader.

Can that be modified somehow to enable 3G data access on a unlocked TP2, either with the stock T-Mobile ROM (which I'd prefer) or with a customized ROM? I mainly want to use the phone for standard, built-in functions and for occasional tethering which I was able to do with the old mocha/locked phones I'm used to. I tried various setting changes for the mobile data connection and I have even tried flashing the phone with the current ROM from the t-mobile website and that changed the boot screen but nothing changed with the data speed.

By the way, the phone does work normally otherwise in all aspects, I am able to browse the web (slowly) and send and receive text messages ok. I also verified I am not being throttled by T-Mobile and I have the tethering option on my account.

Also I did search this forum (and other boards like this) and while I've read references to this issue with other providers I haven't found posts with a fix for this on the TP2 on the T-Mobile network. If nothing else, knowing of ROMS or fixes that are known to support accessing 3G or HSPA on the unlocked TP2 on the T-Mobile network -- or to "lock" or "relock" the phone to T-Mobile which I suppose may also be a fix -- would be appreciated. Thanks!