Converting IDOC-XML to S/MIME

Dear Experts,

I need to send vendor payments IDOC(PAYEXT) to thrid party using https post and IDOC-XML should be in SMIME(signedMIME).

Below are the steps:

1. PAYEXT IDOC XML is to be in S/MIME(Signed with our key) format.
2. S/MIME data to be base64 encoded.
3. URL for posting payment to bank will be  

https://dumy.com/invoke/FMSPartnerInterface.inbound/httpGateway?DataType=PAYMENTS&DataFormat=IDoc-Xml&Protocol=HTTPS&Security=X-509&Data=dGVzdCBtZXNzYWdl

Please note that the data in red will be valid SMIME
file which has been base64 encoded.  The reason for the base64 encoding
requirement is to prevent the data from being URL encoded during the
transmission over the internet.

My question is how can we acheive this in any of standard adapter or using java mapping?

Regards,

Santhosh