Yes i have also problem to convert wma to wav with switch, it is requare to download sony pathes like this. then i have left it, and now a days i am using Sony Forge 7.0. how convert the file wma to wav please follow the some following steps
1 . open the sony forge
2 . now oper the wma file
3 . Save it in wav format.
simple
Regards
Afzal