function FindPrefixForURI(RootNode: IXMLNode; Node: IXMLNode; const URI: InvString; DeclIfNone: Boolean = False): InvString;
__fastcall InvString FindPrefixForURI(IXMLNode RootNode, IXMLNode Node, const InvString URI, Boolean DeclIfNone = False);
This is FindPrefixForURI, a member of class TSOAPDomConv.