I installed the plugin MantisConnect in Eclipse and not make it work...

In the MantisConnect screen in Eclipse I put:
- Name: http://localhost
- Port: 80
- Editing connnections:
- Name: localhost
- MantisConnectUrl: http://localhost/mantis-1.1.1/api/soap
- Brownser Url: http://localhost/mantis-1.1.1
- User: my user
- password: my password
Then I receive this message when I click in "Test connection" button:
"Test Filed. Reason: Teste for MantisConnect URL failed"
"java.net.UnknownHostException: http://localhost"
Is there any additional configuration to do?
Best Regards,
Elias Nogueira