I think it depends on what type of account you have. If you have a consumer level dsl/cable account it's doubtful your ISP will change the reverse lookup for you. I have a business level account with Comcast, and they set my reverse DNS with one easy call. I was actually shocked how easy it was. One of my friends has a business level DSL account with AT&T and they changed his reverse as well.
Release 6.0.2_GA_1912.UBUNTU8_64 UBUNTU8_64 NETWORK edition + Mobile Option
Activesync with Moto Q9C, HTC Touch Pro, Palm Pro, & Palm Pre