Alex,
I have checked it in the docs, and I found it in the .cls as well. I do this in lyx and When I try to set the logopos to empty, it has no effect. I tried your example that works well!
You must have made a mistake as lyx runs the same code in the end. When exported to latex, it looks a bit differently, but it does exactly the same.
Earlier, I had problems with my language extentions, but this not the case. The file using english language. (I would like to use hungarian later...)
If only I had some free time, I would look at that... -Hendri.