I'm not familiar with those panels, but if they connected with flexible tubing, they may be difficult to reconnect if the tubing has hardened. I'd recommend a couple of things:

1. Measure (ideally with calipers) the connection stub on both an old panel, and the new one, to make sure they are EXACTLY the same size.

2. Then go get radiator hoses and clamps to mate them up. There's a good chance your auto-parts store can help find something that will work, in a straight but flexible hose. Just make sure to go when the store is NOT busy; a clerk with a line of people who know what they want is not going to be eager to spend time helping you find something oddball.