The manual for your pump is at
http://www.ismatec.com/images/pdf/manuals/Reglo_Digital_new.pdf
Starting at pg 31, there seems to be a complete description of the serial interface.
The port configuration is 9600 baud, 8 bit, 1 stop bit, no parity.
You could set up a hyperterminal session in Windows to test the commands and then code them using the visa serial communication palette functions.
jc
Mac 10.4
LV7.1
CLD