How to include multiple reference elements within Signedinfo in XMLSignture

I have a requirement Where i need to create an enveloping signature with two reference elements
1) The Input XML
2) Keyinfo

I have achieved creating an enveloping signature with one reference element (input XML) .
I need help to enhance my code to make two reference element under signedinfo the other being Keyinfo tag in my signature.

Kindly somebody suggest how i can i achieve this.

Thanks & Regards
Aman