Noob Question: Icon

When I looked at the new WE, I saw the Option "Import" and that I could select the Path to and Icon with the Units. I downloaded the TFT Beta Pack and wanted to Import the "ObsidianAvenger" Icon inside my Map. When I Import it, the WE puts it in: war3mapImported\BTNObsidianAvenger.blp
Then I go to the Destroyer and select: Art - Icon - Interface.
I then click on the "Import" and the Path it shows me is correct, but in the Game I only get a green nothing instead of my Icon. I have tried to change the Path in the Import Manager to:ReplaceableTextures\CommandButtons\BTNDestroyer.blp
(which is the one Blizzard uses for there reall Icon) but then when I go on Imported it shows me the old Icon, as if the other one has disappeared:( I have messed arround with WinMPQ and Stuff but thats all Way to Complicated for me and I don't want to change everything about my Game, all I want to do is have a different Icon for the Destroyer in my Map. Anyways, why shouldn't I be able to do it with the WE if Blizzard extra includes the Option to? Thx for any Help, I have checked the Tuts and so but somehow they don't talk about the new WE:]

Update: I managed to put the Icon in my War3x.mpq with WinMPQ but it still doesn't work even if I go on Custom and give the Path it should have in the MPQ. When I use Wc3 Image Tool 2.0 it shows me the Icon in the MPQ, the only difference to all other Icons is: Imagemode = 8 and all the other are : Imagemode = 0. I don't even know what Imagemode isemote_confused and of would much rather be able to do it with the WE then MPQ editing