Questions: RhinoCAM or Visual Mill? (since you said out of Rhino, it isn't clear). If VM, which version?
You tried changing the feeds in the feed/speed panel (button in the MOps section of the browser) and it doesn't do anything? What about spindle speed?
If none of that works, it could be that your post has these things hard coded in it (that would surprise me, though) or something else is wrong somewhere.
The feeds and speeds table is not very sophisticated in VM, there is a simple text file called FEEDSSPEEDS in the Data folder in the VM/RhinoCAM root directory, you can edit it with a text editor. You will need to add lines for whatever type of material you use, and create some initial values to test (or get some data from your cutter manufacturer). --ch