When I had to deal with those poorly designed 7 pin connectors, I would use a small bungie to hold them together. I can't believe an whole industry uses those devices.
Once we sold the 5ver, I went back to the connectors with the 6 pin round style. It mirrors the larger trucker style, and has a much more positive connection method.
Our new 2012 Canyon has a factory 7 pin RV connector in the rear bumper, so I had to purchase an adapter for our 6 pin round & 4 pin flat trailer connectors. I'll probably replace the 7 pin with a 6 pin, or perhaps add a 6 pin round in another spot at some point in the future.