Call to Pay by Amazon ConfirmBillingAgreement in Javascript

I need a call to ConfirmBillingAgreement (see page 44 of this document :[login to view URL] ) written in Javascript that can be called from a Node.js (AWS Lambda) function. This is the message that needs to be generated and called. There are Java, C#, Ruby and PhP SDK with this function but not Javascript. here: [login to view URL] [login to view URL] AWSAccessKeyId=AKIAJKYFSJU7PEXAMPLE &AmazonBillingAgreementId=C01-8824045-7416542 &Action=ConfirmBillingAgreement &MWSAuthToken=amzn.mws.4ea38b7b-f563-7709-4bae-87aeaEXAMPLE &SellerId=YOUR_SELLER_ID_HERE &SignatureMethod=HmacSHA256 &SignatureVersion=2 &Timestamp=2013-12-11T11%3A37%3A19.000Z &Version=2013-01-01 &Signature=ET6V00R4fr2inSDky4olLrlS1XrQfdrV9Bj%2BiWebz1c%3D