There seems to be some huge holes in your understanding of how Vegas work flow works. You asked about Keyframing, in reference to reducing the blur on rendered images but mention that the blur results are from your disk burning process. The "seconds per keyframe" setting only pertains to certain renderings such as wmv video files and is one of the parameters that is used to control the bandwidth / file size of the wmv file vs. quality. You can set it high ( more blurry) for smaller files and low to 1 second per keyframe for larger file size ( less blurry ) In the case of rendering to a file for disk burning, there is no "seconds per keyframe" setting because that data is represented in each video frame anyway. In otherwords, it's fixed at the highest setting anyway.
Now that I think I know where your head is at, I believe you may have pulled a piece of information out of a different context and tried to apply it where it didn't belong. Not uncommon around these parts.
But its typical of many who jump in and use Vegas without understanding how this stuff works. We're all guilty of it to a degree.
Of course this doesn't solve your problem but then it does get you off the wrong track for what you want to accomplish.