Compatibility of export presets between CS5.5 and CS6?

I have a ton of custom presets that I've developed over several years. I tried importing them into CS6 by copying the custom presets from here:

\Users\<user_name>\AppData\Roaming\Adobe\Common\AME\5.0

to here:

\Users\<user_name>\AppData\Roaming\Adobe\Common\AME\6.0

I can see the custom presets in AME but only SOME of the presets in the export settings format/preset boxes from Premiere Pro CS6. e.g. AVI show up but not the presets for H264 or Windows Media formats etc (they don't appear).

Are the presets incompatible between CS5.5 and CS6 for some formats (maybe there are new settings that weren't in the old version)?

Thanks,

Paul.