Signed Amazon Web Service(AWS) request subroutine in VBA

Amazon requires all requests to their catalog through Amazon Web Services (AWS) to be electronically signed and time stamped. See [login to view URL] We have an Excel 2007-based application and now need a subroutine to produce the signed and time stamped http request. This project should be very simple for any VBA programer familiar with AWS. The programmer will need to create a free Amazon Web Services account in order to test the routine as, for policy reasons, we will not provide our Subscription ID or Key. The subroutine produced will be incorporated into our existing code by us and the source code will become our property. Below is an example of our existing, unsigned, Amazon request: [login to view URL];AWSAccessKeyId=[AWS Access Key ID]&Operation=ItemLookup&ItemId=[ASIN]&ResponseGroup=BrowseNodes&&Timestamp=[YYYY-MM-DDThh:mm:ssZ]&Signature=[Request Signature] where AWS Access Key ID is our Amazon Access Key ID and ASIN is the ASIN of the item we want information about (eg. ASIN= B00008OE6I).