How can I autoreplay one of my testcases?

You can use test case Teardown scripts to do this. This script should work, but there are probably lots of simpler ways.

// IMPORTANT. CAN CAUSE INFINITE LOOP WITHOUT ITERATOR
for (i = 0; i <1; i++) 
{
	def testCase = testRunner.testCase.testSuite.project.getTestSuiteByName("TestSuite 1").getTestCaseByName("TestCase 1")
	def properties = new com.eviware.soapui.support.types.StringToObjectMap ()
	def async = false
	testCase.run (properties, async)
}