Hi Patricio,
Currently, there is no built-in functionality which allows launching specific test items from the command line. However, we have a script which allows doing this manually. We can provide you with the script if you contact us via our Contact Support form (http://www.automatedqa.com/support/message).
As an alternative, you can try using the approach described in the following forums thread to re-start the failed test items automatically after the test execution is over:
http://www.automatedqa.com/forums/forum/post/?mode=singlethread&thread=37e32d61-6e67-4eff-87d3-f6f5b0135485
