B1if Debugging: red arrows are not displaying on the flow diagram

When you test the processing of the scenario step design by default the integration framework is not displaying the debug information.

Go to the config file, and change the logging level.

C:\Program Files (x86)\SAP\SAP Business One Integration\IntegrationServer\Tomcat\webapps\B1iXcellerator\xcellerator.cfg

Defaults you have to change:
.level= SEVERE
com.sap.b1i.bizprocessor.level = SEVERE
com.sap.b1i.coordservice.level = SEVERE
com.sap.b1i.utilities.level = SEVERE
com.sap.b1i.dblayer.level = SEVERE
com.sap.b1i.xcellerator.level = SEVERE

New values for debugging:
.level= CONFIG
com.sap.b1i.bizprocessor.level = CONFIG
com.sap.b1i.coordservice.level = CONFIG
com.sap.b1i.utilities.level = CONFIG
com.sap.b1i.dblayer.level = CONFIG
com.sap.b1i.xcellerator.level = CONFIG

Re-start the SAP Business One Integration Service, start testing again and voilà: