I finally managed to root my phone like this:
NOTE: This procedure will wipe off all your data, so if you already have stuff on the phone, back it up first.
First, I took out the SIM card.
The links to the files are here:
http://androidforums.com/behold-2-a...n-images-available-latest-t-mobile-stock.html
Next, I made full flash to 1.5 with the file
T939UVJA3-Odin.zip.
Flash this in Odin with One Package UNCHECKED.
Let the phone boot properly, then shut it down.
Next, update to 1.6 stock with this:
Download Behold II T939UVJE2 OEM Odin Files and Instructions
This one needs to be flash with One Package CHECKED.
Again, let the phone boot properly, then shut down.
Last step, the file and directions are here:
http://androidforums.com/behold-2-all-things-root/128131-get-root-based-new-1-6-finally.html
This one also need to be flashed with One Package CHECKED.
After flashing, let the phone boot properly. At this stage, I did not use the superuser.apk that is provided with the rooting files. Instead, I connected to the market using WiFi, and downloaded the newer version of superuser.apk, that is now available on the market.
You can shut down the phone and reinstall the SIM card.
Hope this works for you!