Sometimes you can use the print screen glitch to get inside it. You need to go f3 and look inside, click the INSIDE of the sphere and then very quickly print screen. I have a few times.
Only problem wit this method is that it's like Hotel California - you can go into the Cape anytime you'd like, but you can never leave. No, really. The trick only works going TO the Cape, you'll have to reset to Bonfire to go back.
Simba said that it was solid because people have .fho files that have that ring-sphere mesh "collisioned" - meaning, it's solid in .fho files for OTHER maps. So, unless you want to go through and move your .fho files in/out all the time, you'll have to wait and see if Simba or someone else updates that.