Problems configuring winrm without windows firewall

I'm trying to follow this guide to prepare my server to become a chef-client: http://wiki.opscode.com/display/chef/Knife+Windows+Bootstrap

When I run commands like:

C:\> winrm set winrm/config @{MaxTimeoutms="1800000"}

I get the following error:

WSManFault
    Message
        ProviderFault
            WSManFault
                Message = There are no more endpoints available from the endpoint mapper.

Error number:  -2147023143 0x800706D9
There are no more endpoints available from the endpoint mapper.

After some investigation I found that this is because the winrm service needs to have windows firewall enabled to make any configuration changes. So I was able to set all the settings except for the one listed above either by command line or using group policy management. The problem is that the company provisioned VM has windows firewall permanently disabled and there is no way to enable it, so I can't increase the connection timeout.

The server is running on Windows Server 2008 R2. Is there anyway I can modify this property by altering registry keys or some other method?