are you working with PI stages with integrated drives? In this case a good solution would be the interfacebox C-809 from PI that converts the +-10V signals from the 7344 to PWM signals and provides direct connectivity to NI motion controllers.
Here is the link to the datasheet: http://www.physikinstrumente.de/pdf/C809_Datasheet.pdf
Even if you are not using a PI drive/stage combination this device could be a good solution. Please refer to the specs of your drive.
For the case that this solution doesn't work for you please send me an email (firstname.lastname@example.org) and I will try to find another way for you.
Jochen Klier Applications Engineering Group Leader National Instruments Germany GmnbH