I have the n52te as well and the easiest, most convenient way I have found to transition from key movement to the mouse is to not do it at all ;) Simply remap your direction pad buttons to be your wasd keys. That way you can move with the mouse, the n52 or your keyboard if for some reason you needed to. ( it happened to me, somehow my usb cable got pulled loose and stopped working mid-dungeon...1st-PANIC, 2nd-panic, 3rd-oh yeah! the keyboard!, 4th- remember what it is like to game with a keyboard again)

Anyway, I hope that helps :)

First, DON'T MOUSE MOVE. Use the Dpad on the N52te for movement (Fwd/Back/Strafe Left/Strafe Right). Use the mouse for fine steering using just the right click. This way the mouse is free for target selection, dropping distraction, etc while your left thumb controls your feet. With this I can drop Distract on one side of a target while circling around to where his back will be.
Just make sure to disable the diagonals on the Dpad and it will work fine whatever you have bound. Personally, I prefer leaving the default North/South, East/West values, as those translate to the cursor arrows. If for some reason you have a chat panel open, those aren't captured by the dpad and you won't send someone a "Wasssddsdsswwwss crap i'm dead" message. (Prat and Chatter have options for scrolling through past messages using the arrows.. disable those if you plan on using them for movement.. more chatfrag)

Now for my blatant plug - check out my youtube channel, The 2 Ring (www.youtube.com/user/grendalsh) for vids on setting up and configuring the N52te for WoW, with profiles for most classes (including rogue).

I use an n52te and I move with my mouse BUT, in addition to mouse movement I have the forward and back key bound to their respective keys on the d-pad but I also boud my strafe keys to the left and right, so I get all the possible movement combinations as well as the quick reaction and better control of moving with my mouse. For using spells like distract I hit the button and continue to move forward and strafe with my n52te and cast the spell with my mouse. I also use Opie and a Logitech 5 button mouse to reduce clutter and it works out amazingly. Reminds me of dialing an old phone lol.

To be honest, the n52 is just a little too big for my Hobbit hands. The 15 key is practically useless, and moving with the Dpad while trying to use any of the top buttons is not really possible either. Having said that, I did set it up that way to give it a try. Unfortunately I've already developed some muscle-memory for my old settings. If I don't decide on a strategy and stick with it, I'll be doomed to keep running into the fire instead of out of it.

I'll check out the video, though. Thanks!

Oh, and using the Naga with Opie is a real good setup, by the way.