no idea what the QSS method is.
Much wireless repeating is based on WDS, which requires the firmware to support it as you enter the MAC of the other gadget into the setup of each.
As well as firmware support it is often the case that compatible chipsetsd (ie the same) are also required to make WDS work well.
Google tells me QSS is a security thing, I would start trying to get repeating to work without any security, then increase the security in steps until it breaks the repeating - WDS may only support WEP for example.
MaxDSL - goes as fast as it can and doesn't read the line checker first.
Are your kids pirates ? Limewire, Bearshare, Kazaa, BitTorrent, eMule are all tools of the trade.