I thought I resolved this long ago since I was able to enter URL parameters in WMT. But, since few days ago WMT is reporting duplicated pages for such URL:
When I went to URL Parameters and checked "Show examples" G showed only those like
No examples with slash?parameter. Should it matter? I would think G is good enough to figure this. Why now suddenly this does not work? My parameters were there since the inception of this feature with no trouble.