Hello Upul,
If you are running Q.931 with provider/peer, Display Name is delivered in DISPLAY IE.
First of all you need to check if DISPLAY IE is sent from other side to you.
You can do this by looking into 'debug isdn q931' output.
If it's delivered, then by default GW will send this to CUCM in H225 Facility message which CUCM does not support.
To eliminate this problem you need to have the following command on your GW:
voice service voip
h323
h225 display-ie ccm-compatible
It also might be configured under the voice-class config section.
http://www.cisco.com/en/US/docs/ios/voice/command/reference/vr_h1.html#wp1086686
This will make GW sending additionally H225 Notify message with DISPLAY IE which CUCM will understand.
If you are running QSIG with your provider/peer, it's not possible to deliver CLIP/COLP in QSIG-H323-CUCM design.
CUCM and IOS uses different containers to transport QSIG messages and there is no interoperability between IOS and CUCM if you are running QSIG over H323.
The only possible solution here would be MGCP for that GW.
http://www.cisco.com/en/US/solutions/collateral/ns340/ns517/ns477/ns296/white_paper_c11_459092.html
Hope this help.