XML digital signature addtion

Dear All,

I am new to SAP BC , i have a scenario to add digital signature to XML file placed from SAP R/3 to SAP BC folder.

i have do the flow in BC

1)pick the file from folder
2)add digital signature using certificate provided by bank
3) create Https post method URL to post the document to gateway

please help me and provide the step by step flow to achive the above scenario.

thanks and regards