@ Earowo:
He already finished downloading the installer and is already in pslaunch, updating. Here he won't be able to select a specific mirror.
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@ Vardy:
In general, pslaunch should use a random mirror each time you start it. So if you see that you got a known slow mirror (xordan's is usually slow), it should help to cancel the update and start it again.
If that does not select a different mirror, you would have to edit %APPDATA%\PlaneShift\updaterinfo.xml and comment-out xordan's mirror, renumbering the rest.