Using HTTP From FMS Server 4 to Upload Video

We have an application where a user records video which is encoded by Adobe Flash Media Server 4. We now need to put that file on an S3 bucket to get it into our CDN. Ideally we would simply like to PUT the file to the bucket using the RESTful interface once the encoding 开发者_运维知识库is complete but it looks like LoadVars does not support PUT. So now our two options are:

1. Use multipart/form-data in the RESTful interface, but doing all that boundary stuff looks complicated.
2. Use PutObjectInline in the SOAP interface, but now I have to base64 encode the file, and I don't see how to do that.

You would think that 'encode video, put on world wide web' is a common enough problem but apparently not.

Any suggestions would be appreciated!