This sounds strange. Maybe the obvious, but the roto keyframes only show up if you have a point selected. If you have the overall layer selected, they will not show. If you select a point, than they should appear. If not, please contacts mocha support at: http://www.imagineersystems.com/contact_form and send your project.
Also just to mention, mocha AE CC now has a dopesheet which is a keyframe editor. If you select the dopesheet and twirl down to the layers, you will find your individual keyframe for every animated point.