not sure if this is relevant any longer, however it appears the pfsense / dodo isp problem has been resolved.
I'm running 2.1.3, however I suspect it might be dodo that sorted things out. Looks like they allow an MRU of 1492 now, pretty sure last time I tried this (a year or more ago) they were only accepting 1500 which was causing the problems. Anyway, I hope this may help someone if they are still having issues.
2.1.3-RELEASE (i386)
built on Thu May 01 15:52:17 EDT 2014
FreeBSD 8.3-RELEASE-p16