slovenian-born aljaz bedene secured a british passport last month .
international tennis federation ruled bedene ca n't play for great britain .
ruling comes after bedene played twice for slovenia in 2010 and 2011 .
rusedski , who switched to britain from canada , offered his support .
bedene 's world no 99 ranking puts him only behind andy murray in britain .
murray backed bedene 's switch saying it would motivate those below him .