Microsoft has recently released new version of Linux Integration Service (LIS) to provide compatibility for Linux guest OS under Hyper-V.
This version of LIS supports the following guest operating systems:
Red Hat Enterprise Linux (RHEL) 5.5-5.8, 6.0-6.3 x86/x64
CentOS 5.5-5.8, 6.0-6.3 x86 and x64
Note that in comparison to LIS 3.4, LIS 3.5 expands the list of supported distributions to include RHEL/CentOS 5.5-5.6.
LIS 3.5 is available for downloading using this link
TIP: Download and review Linux Integration Services v35.pdf too