Lee,
I do not have a pop up flash on the D2X so I had to find an alternative making use of the SB80-DX. The thing to think about is due to the very short lens to subject distance high powered flash is not necessary. My bowl diffuser cuts 1 stop of light and even so I had to turn the flash down to 1/16 power.
As you have a pop up flash you have options open to you that I do not. Maybe worth your while looking at setups in an old thread I have resurected. Manual Macro on the Cheap.
http://www.worldphotographyforum.com...ead.php?t=1618
Posts 28, 62, 103, and 104 show options using the pop up flash.
Post 62 shows that at very short lens to subject distances you do not need anything fancy at all. The key thing is diffusing the flash to soften shadows as much as possible. Post any questions you have in that thread and hopefully I can answer them.
Don