Unfortunately, that doesn't really work, especially against good players. The AEC easily out-ranges the faust, and does a ton of damage against infantry - usually taking a model per shot. As a result, a well micro'd AEC is basically impossible to hit, unless they mess up badly.
As for hiding my grens, it's kind of hard when I need to defend a critical point. An AEC can basically run up to some important point (i.e. cutoffs), take out whatever was defending it, clearing the way for the brit inf to close in. Since that infantry is amazing when fighting from cover, it then becomes exceedingly challenging to take the point back - the whole time your falling behind on fuel and/or muni, allowing their advantage to grow. By the time you finally get a PAK or something out (usually around 7-8min mark, especially on larger maps due to travel distance), they've gained a fair fuel/muni advantage against you, not to mention the unit loss from trying to get the point back.
You didn't understand what i was saying.
You have to hide your grens around corners and buildings so you can get close enough to faust the AEC.
Didn't say it was going to be ez but that's what you have to do.