Good question. Altho I do not have a straight answer, as I don't use paid hotspots nor own a MP780.
But I can tell you this: the question isn't the connection, as it is same old TCP/IP networking, which should work fine; the question is whether or not your browser can let you login thru their hotspot page, in order to continue onto the web. Now as far as I know the MP780 comes with a pretty old version of Internet Explorer, so that could cause problem.
Bottom line you just have to try it. They have a free trial right? Or you can wait until someone who's tried it to report back. Sorry that's all the info I have