TC 8.0.3 Agent cannot register from behind firewall / proxy

I have my agent (Windows Server 2008) sitting firewalled from the TeamCity server.

Windows Internet Options have a http proxy configured and I can log on to the TC Server using IE browser from the agent machine.

I additionally have put java and environment settings -Dhttp.proxyHost=abc.de.com -Dhttp.proxyPort=1234 all over the place

and from wrapper.log and launcher.log I can see that these settings actually get picked up in the command lines.

However, the agent does not register with the server and I can see the following line in teamcity-agent.log

[2014-01-27 15:41:32,981]   INFO -    jetbrains.buildServer.AGENT - Build agent started
[2014-01-27 15:41:33,028]   INFO - buildServer.AGENT.registration - Registering on server http://teamcity.abc.de:8111, AgentDetails{Name='abcdef.gh_1', AgentId=null, BuildId=null, AgentOwnAddress='null', AlternativeAddresses=[10.245.11.24], Port=9091, Version='27540', PluginsVersion='NA', AvailableRunners=[], AvailableVcs=[], AuthorizationToken=''}
[2014-01-27 15:41:54,117]   WARN - buildServer.AGENT.registration - Call http://teamcity.abc.de:8111/RPC2 buildServer.registerAgent3: java.net.ConnectException: Connection timed out: connect
[2014-01-27 15:41:54,117]   WARN - buildServer.AGENT.registration - Connection to TeamCity server is probably lost. Will be trying to restore it. Take a look at logs/teamcity-agent.log for details (unless you're using custom logging).

When I compare the netstat output while running the service against what is output when logging in from the browser

I can see that the connection is probably not routed through the http proxy rather then direct.

Is there any other place / option / config that I have to tweak so that the agent seeks connection through an http proxy ?