XML digital signature generated by pub.security.xml:signXML

I have an issue with the built-in service pub.security.xml:signXML. Our customer has an existing .NET program that generates the signs the digital signature and it is accepted on the target system.

I did a test to sign with the built-in service pub.security.xml:signXML and it seems the service adds additional values in the xml by adding <?xml version="1.0" encoding="UTF-8"?> at the beginning of the output and Signature section has the ds namespace added. Is there a way to suppress these unnecessary additions?