Here is the workaround:
In eclipse.ini write the following:
-vmargs
-Dorg.eclipse.ecf.provider.filetransfer.excludeContributors= org.eclipse.ecf.provider.filetransfer.httpclient
-Dhttp.proxyHost=*myproxyhost*
-Dhttp.proxyPort=*myproxyport*
-Dhttp.proxyUser=*proxy username*
-Dhttp.proxyPassword=*proxy password*
-Dhttp.nonProxyHosts=localhost|127.0.0.1
After starting eclipse verify, that you use the Manual proxy method.
HTH