code: public DialogActivity getNewDialog(Address from, Address to)
  			throws SipException {
  		checkState();
  		if (from == null) {
  			throw new IllegalArgumentException("From address cant be null");
  		}
  		if (to == null) {
  			throw new IllegalArgumentException("To address cant be null");
  		}
  		return _getNewDialog(from, gov.nist.javax.sip.Utils.getInstance()
  				.generateTag(), to, null);
  	}
docs: /*
  (non-Javadoc)
  
  @see
  net.java.slee.resource.sip.SleeSipProvider#getNewDialog(javax.sip.address
  .Address, javax.sip.address.Address)