Reply to Numark DJ io sound card and snow leopard help

Going crazy here hopefully someone can help me shed some light on this subject. Just purchased Numark DJ io sound card and a pair of Mackie MR5 speakers. when i plug in my soundcard on newest snow leopard on my imac 24 the volume sets to max and is grayed out so i can not adjust. i can not find anything on the net and have not received a message back from numark support. I am using the latest driver. This is a huge problem because my speakers do not have volume control.

any info much appreciated
thanks