What method are you using to combine the Projects? The more completely you list your steps, the easier it might be, to spot the issue.
Also, AVCHD is a camera format, using the H.264 CODEC. You can output to several flavors of H.264, but not actually AVCHD, specifically.
I haven't even started to combine the files because the ones I have created from existing projects have no audio. I created them by opening an existing project and then selected the share to computer option then I selected the AVCHD option. When finished sharing, the AVCHD file that I want to combine in the new project contains no audio, I must be doing something wrong.
That did help Bill. I appreciate your advice.
Best to you and your family for Christmas and the New Year!
Glad to have provided a helpful answer. That is what we try to do with every post we make.
Merry Christmas and the happiest of Holidays to you, and yours, as well.
Good luck, and happy editing.
PS - if that did answer the question, you might want to take a look at this article: http://forums.adobe.com/thread/1058744?tstart=0