RPManager has support for 3rd party renderers.

There is an RPM tab for 3rd party renderer controls, but if this does not exist for the renderer you are using, or if it does not contain a parameter you want to edit, you can use the standard 3dsmax render dialog if you edit 1 pass at a time.

3rd party objects can be controlled via the Object Property system if there is scripted access - the 'Get Props from Selected Object' button at the bottom of the Custom Properties column will attempt to load the properties of the selected object into this custom list, and once picked they will be controlled.

For controlling vray object properties per pass, capture the 'UserPropBuffer' in the Custom Properties list.

One renderer specific control is the Vray Cache Manager, information about this can be found here