Guys, just for clarification, smoke grenades WERE NEVER used by squads for any tactical maneuvers on any front. This is a common mistake many people make based on the fact that a lot of games (such as COD, BF 42, etc.) allowed smoke grenades for gameplay balance.
The only thing smoke grenades were used for by squads in WWII was for emergancy signaling. However, smoke canisters were attached to many German tanks and were released to screen infrantry movements and provide immediate cover from any anti-tank threat. Also, some mortar guns could fire smoke rounds to cover infrantry assaults.
However, a lot of soldiers were equipped with white phospherous grenades. This looked like white smoke but actually was an incendiary device. When it comes in contact with air it becames an incendiary and when it touches human tissue, it burns it away. It was used on all fronts and most noteably in the jungles of the Pacific war. Again, however, it was ment to route out entrenched enemies and wasn't specifically ment to shield movements or advances.
I think it would be cool if a commander in game could call in smoke screens on a limited basis like you can call in arty. This would be historically accurate and help a lot with team work/gameplay.