Slownick's dashboard

Hey folks, I am new to Wuala and donwloaded a file from a friends group, after this I wanted to keep this file on my HD, so I thought I just could copy it from the Cache to another place I like and rename it. But I was stupid as it is still encoded, so I could not open it. Then I renamed it to the original Cache name and placed it back, but Wuala did not recognize it as downloaded. I know it is no prob to down it again. But I just want to know if I can get Wuala to recognize it again as already downloaded.