The drivers from D-link aren't fully supported by WM2003 yet, they are apparently releasing some soon.... here's the blurb.
Does D-Link offer Microsoft® Mobile 2003 drivers for the DCF-660W Compact Flash wireless adapter?
Currently, D-Link does not offer Microsoft® Mobile 2003 drivers for the DCF-660W. D-Link is working on development of drivers and will post them at http://support.dlink.com/products as soon as they are available.
Estimated time of release is mid-August. Time is subject to change.
We do NOT claim support or drivers on the box or website for Mobile 2003. Do not assume that it will work with an operating system not listed on the box. Please do not hold on to product in anticipation of driver release.
Some users have been successful using the latest drivers. We have tested the drivers below and were successful using a Dell Axim X5.
I have WM2003 and no, the option to turn off the wireless signals is NOT available.
Patience my friend for we shall have that option soon. :D