I discovered something quite amazing on the Global Trading thing in Diamond/Pearl.
Edit: I really discovered how it works now
It's really hard to get a dusknoir and those trade guys because people alway want lv 100 deoxys and stuff. I discovered a way to evolve your trade guys without having to get those guys in trades.
On the GTS, Offer whatever trade guy you want to evolve. Ask for something impossible to trade such as a lv 2 Kyogre or something, so it doesn't get traded. (this finally makes sense why people ask for impossible things!) Now make any trade on the GTS, which granted, can be difficult.
Once you traded something, take out the offered pokemon, and it will evolve.
Edit: I really discovered how it works now
It's really hard to get a dusknoir and those trade guys because people alway want lv 100 deoxys and stuff. I discovered a way to evolve your trade guys without having to get those guys in trades.
On the GTS, Offer whatever trade guy you want to evolve. Ask for something impossible to trade such as a lv 2 Kyogre or something, so it doesn't get traded. (this finally makes sense why people ask for impossible things!) Now make any trade on the GTS, which granted, can be difficult.
Once you traded something, take out the offered pokemon, and it will evolve.
Saturday dude. 
