Sony Ericsson SDK Connection Proxy Woes

I just wasn't able any more to upload software to my JavaME phone with the Sony Ericsson SDK - one problem with the Connection Proxy after another. Tried this and that, restarted the SEMC service, rebooted phone and computer, to no avail - until I plugged the USB cable into a different port. WTF... But that might have to do with my cat chewing on the cable, so maybe moving the cable "fixed" a broken wire, for the moment...

Another thing: What COM port should you configure the connection proxy for? Hint: Using the Windows Device Manager, it will be not listed as a normal COM port (though the entry "Sony Ericsson Device xx USB WMC Device Management (COMy)" does look enticing and the proxy will connect to this port, but uploading an application will not complete successfully).

Look under "Modems" instead: Right-click "Sony Ericsson Device xx USB WMC Data Modem", select "Properties", select the "Modem" tab, and voila: The COM port you need is listed on top.