cassette toilet in Starcraft Venture

[dandreas]

This is my first experience with a pop-up since I was a kid.  And that thing was pretty primitive.   We just got a new to us 1999 Starcraft Venture with a built-in shower/cassette toilet area.  I understand the concept of how the toilet should work as I have used porta-potties before, however I can't get the "rinse" button to work.  I don't have the manufacturer's guide so I don't know if I am missing a step when trying to work it.  And yes, before anyone asks, I filled the water tank.  The button only depresses about an inch and a half or so.  Should it be pulled up first?(I tried to pull on it a little, but that doesn't seem to be it.)  Is there some sort of trick to this or is my water tube just not attached properly anymore?  And is there any easy way to fix this?  The whole toilet seems to be one big molded piece and the access door from the outside is too small for me to see anything.  How can I get to the tube if need be?  Any input would be great.  At least the button rotates so I can "flush" everything down.  I'd just like to be able to rinse it each time without a bottle of water this next trip!  Thanks everyone!