Dear mao1 and Tim O,
maybe it is not longer of interest, because just one year ago, but I found a solution:
On the newport download page
ftp://download.newport.com/New Focus/Motorized Components/Intelligent PicoMotor/
you can find the Labview codes to address the device.
It's the 'example-labview-MCL.zip, but you can also try the other files.
There's also a terminal emulation program, which (in my case) is communicating directly with the device and quite helpful to check the communication.
Remember to initiate the device withe the com settings properly before you perform.
A complete listing of the commands can be found in the manual and if you do not have it, it can be downloaded here:
http://assets.newport.com/webDocuments-EN/images/15238.PDF
Hope that works for you, too.
Actually I'm interesting to integrate the device also in MicroManager, a program controlling diverse microscope attachements
(http://valelab.ucsf.edu/~MM/MMwiki/).
They claim, that using a certain device could be easy to make any stage working in that program. e.g.
http://micro-manager.3463995.n2.nabble.com/Serial-port-controlled-stage-td7220452.html#a7223487
(This is not an affront towards NI!!!!)
Best regards (and please tell me about the results)
Thomas