I have been editing for years on FCP 7 and just finishing up my first project on Premiere. I usually give my sound mixer an OMF with 1 second handles from FCP 7. I was told I should export an AAF from Premiere instead of an OMF because the OMF is so huge it crashes the system. But I can't figure out how to/where to add handles for the export.
to answer your actual question about aaf.
I suspect that in your AAF export settings window, you have "copy complete Audiofiles" selected in the Render field??
If you change this to "trim audio Files" this allows a Handles frames entry to be made.
As a dubbingmixer Id recommend 50f unless your sound man asks for different, and make sure you EMBED the audio in the Files Window.
That should do it.