Need help with many-to-many relationships

Being new to Rails, I would appreciate some help defining some database table relationships. I have the following tables:

waypoints     id     name

routes     id     name

routepoints     route_id     waypoint_id     seqno

This leads to the Rails associations:

waypoints   has_and_belongs_to_many :routes, :join_table => "routepoints"

routes   has_and_belongs_to_many :waypoints, :join_table => "routepoints"

My problem is that routepoints defines an ordered list of waypoints for a given route (using "seqno"). Is it possible to use acts_as_list somehow? I will also need other attributes of routepoints (like estimated time enroute, fuel burn, etc.).

Any ideas appreciated!

Thanks, Josh. Exactly what I needed...