There was no music before so I added and PE3 began to behave normally!
I can obtain mpeg2 or HDV whatever I need!
But what makes me glad is to see that, before, when there was no audio, DVD Architect 5.0 was not seeing that m2t's but after adding audio it began to see these files, with music!
So this means to me that I will be able prepare some parts of my future BD's with PE3 besides Vegas Pro 8.
Thanks a lot Paul:)
I know very well that I have I lot of things to learn...