Send XML file from Dynamics CRM to REST API URL

We are looking for someone who can help us integrate Dynamics CRM with an external API. We already have a Dynamics CRM Action that takes as an input the invoice GUID and outputs the XML file. We just need someone to develop a custom workflow activity for Dynamics CRM On Premise that we will execute through a workflow when the invoice status changes to paid and send the content of the generated xml file directly to the API. The API documentation can be found here: [login to view URL] Please read the API doc carefully before bidding and ONLY when you are safe that you are able to do this, be ready and write me that you have understood in your bid. I will contact you and give you the API secret key and when I give you the Key I will also give you an example XML file. I need you to have the key and xml and create an invoice in this platform using the key and invoice. Once you have proved us that you know how to do this we will assign the project and complete the creation of the Dynamics CRM Workflow activity. No access will be given to our servers so you should consider this project if you have a dynamics crm trial organization setup or we can give you access to our trial organization. You have to prove us that you know what you are doing, you know how to comunicate with the API that we will give you and you know how to create a custom workflow activity. Milestone will be released only after we have tested the custom workflow activity and we have the source code to check the quality of your work. We will provide you with our code on how the XML is being generated so you could reuse that code on your custom workflow activity if you want. Happy Bidding