code: public B2buaHelperImpl getB2buaHelper() {
              B2buaHelperImpl helper = null;
              SipApplicationSession applicationSession = getApplicationSession();
              if (this.isValid && applicationSession.isValid()) {
                  helper = (B2buaHelperImpl) applicationSession.getAttribute(B2buaHelperImpl.B2BUA_ATT_NAME);
              }
              if (logger.isDebugEnabled()) {
                  logger.debug("B2BUAHelper got:" + helper);
              }
              return helper;
  	}
docs: {@inheritDoc}