You could simply multiplex the audio and video part using simple MPEG tools in TMPGEnc.
Get TMPGEnc (it’s freeware) from http://www.tmpgenc.net (click on downloads at the *top* after you select your language). Open TMPGEnc, skip the wizard. Click on File, MPEG Tools, then multiplex tab (MPEG-2 (Program) I think).
