I do a lot of voiceovers, but I don't use the mic recording feature built into VideoStudio. I always record it on a recorder (either my video camcorder or a separate audio recorder) and import the file into VideoStudio's library. I never have any problem with this, but that doesn't help you with your workflow.
I suggest simply speaking your voiceover into your video camera, loading the file into VS's library, then dragging the file to the audio track. (Yes, you can drag a video file to the audio track.) A big advantage of this is that you get the same quality of sound that you get with the camcorder's built-in mic, since that's the mic you're using for the voiceover.
Of course, if you use the camcorder with a plug-in mic (such as a lavalier), you can use it to record your voiceovers onto the camcorder. Again, you'll get the same quality recording.
If that workflow suggestion doesn't work for you, then I don't have other ideas for you. Perhaps someone else will come along who does.