How to Upgrade to EMC v8 without internet access?

[htw]

Hi,
we are using virtual Management Center 7.1.2 connected to an internal network. For Update Checks we are using a webproxy which is configured in EMCs Settings.
Release Notes says that you need internet access during upgrade. I tried to update our test-EMC but it failed because of lack of internet. Obviously the webproxy-settings within EMC are not used during upgrade. I thought about editing webproxy-setting into Ubuntus etc-Files but I am not sure if this would cause problems during upgrade.

Whats the simpliest or most supported way to upgrade an EMC without direct internet access?

[htw]

Hi Zdenek,
our Test-System is also in an private management network with proxy server. 

[Zdeněk_Pala]

Install new EMC version 7.1.2 to the lab = place where you have internet access, move config from production to the lab (backup and restore). Upgrade the lab to the version 8.0.2.42. Deploy new 8.0.2.42 on the production and move the config from lab to the production (backup and restore). This is the process I used. May be someone does have better procedure. Regards Z.