code: public void removeTransaction(String branch) {
  		synchronized(this.ongoingTransactions) {
  			TransactionRequest remove = null;
  			for(TransactionRequest tr : this.ongoingTransactions) {
  				if(tr.branchId.equals(branch)) {
  					remove = tr;
  					break;
  				}
  			}
  			if(remove != null) {
  				boolean removed = this.ongoingTransactions.remove(remove);
  				if(logger.isDebugEnabled()) {
  					logger.debug("Removed transaction " + branch + " from proxy branch ? " + removed);
  				}
  			} else {
  				if(logger.isDebugEnabled()) {
  					logger.debug("Removing transaction " + branch + " from proxy branch FAILED. Not found.");
  				}
  			}
  		}
  	}
docs: https://code.google.com/p/sipservlets/issues/detail?id=238