Yep, but a parallel port card or USB to parallel converter is a lot cheaper to add than an Arduino with a USB programming interface. If you've already got the servo controller (a Lynxmotion SSC32 has inputs and 32 servo outputs for $40) there's no need for other controls.
The problem is just that VSA is only setup to support DMX lighting controllers for other than just on/off control.
How many bits of output are you getting from the servo stream?
More information about formatting options