Known communities for AS174?

Hello, I'm looking for a way to do path prepending for my prefix as it leaves AS174 (Cogent), one of my upstreams. The following: http://www.radb.net/cgi-bin/radb/whois.cgi?obj=AS174 suggests that at least as recently as last May they might have accepted: 3. Communities controlling Cogents AS path prepending for customer routes on egress: community effect 174:3000 do not announce 174:3001 prepend 174 1 time 174:3002 prepend 174 2 times 174:3003 prepend 174 3 times But I've tried setting each of those and it doesn't seem to have any effect. Anyone know if that info is out of date or maybe has something else to try? Thanks, David