[CentOS] gtkmm 3.0?

I am a newbie so this may be a question with an obvious answer.

Is there a (practical) way to get gtkmm 3.0 on Centos 6.  It comes with 
gtimm 2.4 and at one point in my random surfing, I thought I found the 
newer version in the testing section.  But I am having trouble getting 
access to the packages in the testing section, and am not entirely sure 
what to do if I actually could get access.

Any help would be appreciated (or suggestions about where to look for help).

Many Thanks.

Andy Gilman