Adding namespaces to XML Document. Siebel EAI

Hi,

We have a requirement to make a REST XML call. The Request xml which has to be passed has the below namespaces and more.

xmlns

xmlns:xsi

xsi:schema location

.

.

After adding the IO / IC User properties we get the xmlns property only and not the xsi:schema location and few more custom namespaces.

Ex. (Just for depiction)

<OrderDetails xmls="..." xmlns:xsi=".." xsi:Schemalocation="...">

...</OrderDetails>

Can you please suggest on how to add additional namespace declarations in the root nodes in XML separately. Are there any vanilla business services that can add these attributes to the XML Doc.

Thank You.