Misleading Rights errors in HEAT/ITSM integration

This error occurs when trying to integrate one of the ITSM modules (to at least version 5.03) with an existing HEAT (version 8.36) implementation. When trying to access the module (in this case configuration) the user is presented with the error "You do not have rights to view inventory items". After inspection of their user account in HEAT and ITSM it is clear that the user has enough rights and has been created in ITSM with the correct role to allow access to this Module. The error is actually indicating that the passwords do not match between the HEAT and ITSM systems. For integration to work correctly the Users need to be created in both HEAT and ITSM with the same username and password.