TMPGDVD author no audio in motion menu

Hi produced the files from a toshiba DVD recorder in VRO format on a RAM disc and left unedited. Imported files into my PC and edited using MPEG2VCR. Saved file into MPEG2 format. File plays fine in Power DVD and WM9 and MPEG2VCR with audio. Using the above file produced a 55 sec sequence to be used as background for the motion menu, this also plays with audio as above. When i open the file to select it the Speaker icon is greyed out, this applies with the 55 sec segment or even the full 40min file. Pressing ahead and producing the DVD. Perfect, the menus look and work great, BUT no audio as the motion menu plays. Select a chapter, play, and works great. Anybody got any suggestions, have i missed something. On the menu display settings,motion tab i have selected the bgm option.
Many thanks for any suggestions

What form is the Audio in ? PCM, MP2, AC3, etc ?

audio is ac3 . i have now realised from a reply to another thread that ac3 does not work in motion menu on TMPG author. I extracted it with DVD2AVI and produced a compliant file in tmpg enc. menu now works great. Thanks for the reply.