Understand hixie-76/hybi-00 WebSockets
The flash proxy connector (client transport plugin) understands only the RFC 6455/hybi-10 type of WebSocket, which is supported by Firefox 7+, Chrome 14+, and IE 10+. Safari 5 only supports the older hixie-76/hybi-00 type of WebSocket. (https://developer.mozilla.org/en/WebSockets#Browser_compatibility.) The connector should support this type of WebSocket so that Safari can be used as a proxy.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information