Man, I just did that last weekend, and it was a b--ch figuring out how to disconnect that connection between the filter and the engine. The trick is, once you get the tool into that sleeve in the fuel line, you have to swing it back and forth using the same motion as when you're using a socket. That's the motion that disengages the inner clips. You gotta use that same motion when connecting the new filter.
Good luck my brother...