SOAP 2001 support in IS 4.6 -- need help

One of our customers can’t receive SOAP messages from us because their parser wants the following headers:

xmlns:xsd=“XML Schema
xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance

IS 4.6 generates SOAP messages specifying the 1999 XML standards (eg. xmlns:xsd=“http://www.w3.org/1999/XMLSchema”). Can I override this somehow?

I hope someone can help.

Edwin.