You will normally upload RTML via the ACP main web user interface, in the Scheduled section.
If you are a programmer and wish to submit RTML requests to the Scheduler, and if you are skilled in HTML file uploading and Ajax, you can submit observing requests directly into the schedule database via an HTTP file-upload POST request. The receiver script for RTML submissions is the file asuploadrtml.asp, an Active Server Page, located along with the rest of the ACP support files in ACP's WebDocs\ac\ folder.
Your task, then, is to write code which constructs and sends a proper multipart/formdata POST request to the asuploadrtml.asp script at the ACP server. The file is the RTML document. No other form elements are processed by asuploadrtml.asp. You will get an HTML response back from the server indicating success or failure, along with an error message if the RTML failed. The error is usually indicative of an error in the RTML itself.
Please feel free to contact DC-3 Dreams for help with this if you wish.