SRM Content data type adding...

Hi Guru's,

I need to add the subelement in my SRM content structure of the http://sap.com/xi/SRM/Basis/Global namespace.

I can see the 2 elements. MessageHeader and PurchaseOrder. I want to add few data types in the PuchaseOrder--> Item. Under the ITEM node I want to add few elements.

I can add only in the same level of MessageHeader and PuchaseOrder. I am not able to add the elements under the Item.

Give me the soultion to add the field in the Item level.

Thanks,

Jane.