done that also....
here what is did..
i installed the amber by NSU ( lost all apps after update as there was pro cam app, but not working as it needs amber update )
after that i updated to amber lose all apps..
again went to setting connected to wifi and change the proxies as mention...
but connecting to store it shows not data cannection and checking the pro cam app throug I.E on mobile it shows device not supported.
rgd
ankit
Here is what I can suggest.
1) Connect phone to pc.
2) Update to amber again. I'm assuming you don't have anything installed, so flashing shouldn't be an issue.
3) Once flashed, sign in to your microsoft acc. Let the account sync and try to access store without proxy.
4) Once you ensure everything is working fine, go ahead with the proxy settings and download Pro Cam.
It happened to a friend who has the Cyan Lumia 720, that inside store he didn't have "Apps from Nokia" option. He did a hard reset and synced his microsoft account before trying again. After syncing it seemed to work.