Code Page Error

Hi All

We are installing SAP NW EHP4 ECC system in distributed environment. We have successfully installed the ASCS instance in ASCS primary node with unicode kernal. We need to installed the DB ( Oracle 11 ) on the seperate node. While installation in sapinst gui , in one screen it ask for code page and took default value as 1100. But when we changed it to 4201 ( for unicode ) , sapinst don't accept. Further going with 1100 its accept the non unicode kernal.

Kindly suggest why it is taking for 1100 codepage as default if someone has seen this problem.

Thanks for your time in advance,