soapUI 4.5.1: how to read from excel file for load test

/*
@Description : Data Source Looper responsible for looping a specific teststep.
@GroovyTestStepName : "GroovyScript-SaveDataSource"
*/
def myTestCase = context.testCase
def runner
propTestStep = myTestCase.getTestStepByName("Properties-Looper") // get the Property TestStep
endLoop = propTestStep.getPropertyValue("StopLoop").toString()

if (endLoop.toString() == "T" || endLoop.toString()=="True" || endLoop.toString()=="true")
{
 "sleep(100000000000000000000000000000000)" 
log.info ("Exit Groovy Data Source Looper")
assert true
}
else
{
 "sleep(100000000000000000000000000000000)" 
testRunner.gotoStepByName("GroovyScript-DataSource_Save")
testRunner.gotoStepByName("GroovyScript-DataSource_Contact")
testRunner.gotoStepByName("GroovyScript-DataSource_Mobile")
testRunner.gotoStepByName("GroovyScript-DataSource_Service")
testRunner.gotoStepByName("GroovyScript-DataSource_Work")
testRunner.gotoStepByName("GroovyScript-DataSource_Callback")
//setStartStep
}