code: public void associateServerTransaction(ClientTransaction ct, ServerTransaction st) {
  		if (ct == null) {
  			throw new NullPointerException("null client transaction");
  		}		
  		if (st == null) {
  			throw new NullPointerException("null server transaction");
  		}
  		final ClientTransactionWrapper ctw = (ClientTransactionWrapper) ct;
  		final ServerTransactionWrapper stw = (ServerTransactionWrapper) st;
  		
  		final DialogWrapper stDialog = (DialogWrapper) st.getDialog();
  		if (stDialog == null) {
  			throw new IllegalArgumentException("the specified server transaction has no dialog.");
  		}
  		
  		ctw.setAssociatedServerTransaction(((ServerTransactionActivityHandle) stw.getActivityHandle()).getTxId(),true);
  	}
docs: /*
  (non-Javadoc)
  @see net.java.slee.resource.sip.DialogActivity#associateServerTransaction(javax.sip.ClientTransaction, javax.sip.ServerTransaction)