Howdy hp8703B,
One great place to check for available drivers is the National Instruments
Instrument Driver Network. However, I checked into your driver and was not able to find it. In these cases, you can definitely
create your own driver or contact Agilent to see if they have one that has not been posted to the Instrument Driver website yet. Another option is to use a simple GPIB/serial connection and the specific commands for your instrument to communicate. You would find these commands in the manual for your hp8703b.
Sincerely,
Chris G in AE