Custom Taxonomy Permalinks

I have created custom taxonomy ‘Prod_cat’ for products category
than i have inserted new category as below in hierarchical mode
wireless-system (parent cat)
– wireless-presentation-system (sub cat)
– wid340-series (sub sub cat)
– wid440-series (sub sub cat)

When I opened this as below it works proper
http://site.com/prod_cat/wireless-system
http://site.com/prod_cat/wireless-presentation-system
http://site.com/prod_cat/wid340-series
http://site.com/prod_cat/wid440-series

But when I remove slug “prod_cat” using rewrite rule only parent category works and others give 404 not found error

http://site.com/prod_cat/wireless-system – working
http://site.com/prod_cat/wireless-presentation-system – not working
http://site.com/prod_cat/wid340-series – not working
http://site.com/prod_cat/wid440-series – not working

And also i want to open this url with .html extension
So, any one can suggest me for this.