Been testing out the version of the ASL used in libertyernie's Classic Exp. Pack and it seems to work fine with my BrawlEx setup. Just wanted to forward it here since I know it's been highly anticipated by some of us:
http://forums.kc-mm.com/index.php?topic=20291.0YES!!! I got it working in my setup too. Thanks for sharing that link! Time to mark the AFL for stages as obsolete!
A few notes for anyone who tries to use ASRL with Brawlex:
1. The layout of the custom SSS code that accompanies the new ASRL is slightly messed up but well documented. You can use your old custom SSS code and just replace the new STGCUSTOM26-28 if you want too. Switching the association of STGCUSTOM26-28's stage cosmetics with their replaced stage is easier than making whole new stage cosmetics (and PAT0 entries...).
2. Big Blue is missing from the ASRL setup but it works fine if you add it. (Unlike Castle Siege and Lylat Cruise)
3. The DATA section of "ASRL - Stages" and "ASRL - Modules" codes are identical (except Flat Zone 2, which uses 0x47570E50 for "ASRL - Stages" and 0x47570E52 for "ASRL - Modules" (credit to secretchaos1)). The ASL tool edits the "ASRL - Stages" code so you can just copy over the changes for the "ASRL - Modules" code, with the exception of Flat Zone 2.
4. The old Custom Sound Engine is incompatible with the new ASRL. The new Custom sound engine must be used. Keep in mind that it loads files from a different location and has slightly different acceptable filename ranges.
5. The Tracklist Modifier code is compatible with STGCUSTOM26-28 too (don't forget about the byte count!)