That's a pretty complicated way to edit, SiriNeos!
Most people who use Premiere Elements in version 7 merely convert the AVCHD to HDV, which edits pretty efficiently. Doing so may save you a few steps.
As for the Panasonic TM900 -- one word of warning. This camcorder shoots in 60p and 50p. I recommend against shooting in those formats if you plan to edit in Premiere Elements. But stick with 60i or 50i and you should be fine.
This ARTICLE discusses using proxy files for editing AVCHD. Some have found that by using CineForm, they can also edit AVCHD material on underpowered computers. Think that the CineForm program used is NeoScene?
It is not complicated because I automatized it (In 2 minutes I prepare the proxy generation of many HDV or AVCHD files (100 or more))
Your advice related not using 60p is not for me. I converted the 50p-AVCHD-TM700 file to a 50p-DV file as I explained you and the edition in PE7 is very fast.
My problems are related with audio, not with video.
My question was not answered. Does anybody know the right compression audio codec I must use in VirtualDub to obtain an AVI file considered by PE7 as a 5.1 audio (6 chanels)?
Thanks in advanced.
The DD AC3 CODEC is used for both 2-channel (stereo) and for 6-channel (5.1 SS).
Now, I produce all of my AC3 DD 5.1 SS from PrPro with the Minnetonka SurCode DD 5.1 SS plug-in, so cannot comment on using other programs. This THREAD (see D&R Films' Reply) steps through the production of DD 5.1 SS with Audacity, and probably another utility. As I do not need that workflow, I have never investigated it. For some reason, I cannot find Terachild's original post, but think that D&R Films has copied most of it.
Now, PrE can Import fully DD-compliant AC3 SS files, and easily into a Project set up for DD 5.1 SS, but cannot directly Export/Share to DD 5.1 SS. There will be a stereo (2-channel) mix-down. PrPro can directly Export the DD 5.1 SS, but only with the SurCode plug-in.