In the operation - Machine Control - Start of Path Events - add Set Modes - Feed Rate Mode - set it to Inverse. At the End of path events set feed rate back to IPM or whatever you need. In post builder in Machine Control - Feedrates - FRN Mode - set G93 and Format max = 999999.999 and min = .001.
Hope this helps,
Rick
Win7 64 bit w/NX9.0.3.4 MP9 and NX10.0.2
Vericut 7.4