Try and work in some eccentric heel drops into your training program, if you haven't already. I believe these take a little while to become effective, but should be useful as your mileage increases.
My achilles problems were caused I think by weak core and glute/leg muscles, leading to poor running form on longer runs. I'm finally doing a strengthening program to address those specific issues, and my form has improved already - I haven't had any achilles tendinosis problems for a year or so anyway, but I'm sure these strengthening exercises, allied with heel drops, will help keep me safe from a recurrence. Not sure if you're doing any specific strengthening stuff, worth a try if not.
I wore an achilles/ankle support while I had achilles problems, it didn't make any difference for me, just stopping for a short while helped more. My last instance of this stopped me running for six weeks and I couldn't shake it off entirely for eight months, so take it easy!