This functionality has been available since 12.0(27)S.

http://www.cisco.com/en/US/products/ps6017/products_feature_guide09186a008041805b.html

Please refer to the Cisco Feature Navigator to find out which other IOS releases and platforms it is supported on:

Check for this specific feature:

MPLS LSP Ping/Traceroute and AToM VCCV

Cisco Feature Navigator:

http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp

As to your other question, you can generally ping and traceroute to the customer network from the PE provided that the address you are using for the ping/traceroute is present in the VRF of the specific PE. This would exclude MPLS ping and traceroute thoug, if this is what you are asking.

Hope this helps,