on Boba and Jango the hoses connect to the fuel cells for the jet pack, yes they do run up through the short sleeve, but they go on through the backplate into the jet pack, that's how the flame thrower works.
For the gauntlet hoses, I run mine up the outer sleeve and have a set of parachute clamps attached to elastic inside the top of the sleeve. The other end of the clip is on the top of the hose, so I just clip them in. Te elastic allows the tubes to move with you without affecting your gauntlet or letting the top of the hose show.