Hi!
I have solved the issue: in oredr to receice the TGT you need to send your login details (username and passwodr) to the following link:
https://your_cas_server:cas_port/cas/v1/ticketsand set the "Post QueryString" check box.
Add the assertion for the responge:
import com.eviware.soapui.support.XmlHolder
def holder = new XmlHolder(messageExchange.responseContentAsXml)
holder.namespaces["ns"] = context.expand('${#Project#BASE_XMLNS}')
log.info holder.getNodeValue("//html[1]/body[1]/form[1]/@action") // the path to your responce TGT
def TGT = holder.getNodeValue("//html[1]/body[1]/form[1]/@action")[55..116] // pars the responce and write to the TGT variable your TGT
log.info TGT