replacing center fuel tank but need advice

[bf5113]

The center fuel tank on my '93 F-150 started leaking so I bought a new tank and am in the process of installing the new tank. Got the tank strapped in, but am having problems re-attaching what I believe is a venting hose (it connects to the 1 1/2 inch hole in the top of the tank). Tried using a small screw driver to push the bottom of the rubber connector into the hole, but can't keep what I've forced in to stay in as I try to push the rest of the connector in. Any suggestions in dealing with this problem would be appreciated.