Mailing List Limitations with Squirrel Mail/Dreamhost

I’ve been having issues with squirrel mail/dreamhost limiting the amount of email sent out from a clients squirrel mail address to 100p/hour. Does anyone know of a way there a way around this limitation? The mailing list messages are generated and put out by a service called Aweber, but that doesn’t seem to be an issue.
Any recommendations or solutions would be appreciated, thanks!

this might help: