RDNIS and SIP

I understand that the RDNIS is located in the diversion header. When a call comes in via SIP we are taking the actual phone number out of the header’s “to” field so that we can make it the RDNIS. The problem is that when the call gets forwarded it does not forward the RDNIS information. There has been a dump of the output generated by Asterisk and for the PRI calls it shows Information Elements for everything including the RDNIS (IE 6, Variable Length IE, Redirecting number…) but when it comes to the SIP calls it does not have the “IE6…” information.

We are just wanting to send the RDNIS with everything else and it is not populating for some reason. If anyone has any idea as to why it is not and/or how to make this happen it would be greatly appreciated. Thanks.