Lets get to the point straight!
You have to open a *.jar file for example in WinRar and than open file "manifest.mf" from folder "META-INF". Than write there this in the end:
First is original resolution of game and the second is the resolution of your phone."
Open the jar(with winrar)
->Open manifest.mf(drag it to your desktop and open it with notepad)-add the two lines Nokia-MIDlet-Original-Display-Size: 176,208 (the original resolution of the game)
Nokia-MIDlet-Target-Display-Size: 352,416 (the resolution of you phone)
->Drag the edited manifest.mf back to your jar(in meta-inf directory)
->Send to phone