Auto Update behind an http proxy with credentials / error 23

[lab34]

Hello,
Thank you for your job, I like this browser !

I'm behind a corporate proxy.
When I want to check for update on the menu, it gives me "error 23"

I've did a Wireshark capture, and I saw that the proxy was answering http 407 - authentication required

Could it be possible to ask the credentials ?
Or, as a fall back, store the proxy address and credentials in an ini file ? (in the model of the startup command line)
Or, to use the http_proxy environnement variable ?

best regards