[otrs] OTRS Integration with other tools

Hello All, We want to understand if OTRS can integrate with proprietor system like HP EMS or BMC Petrol. While using OTRS, we would like to continue using proprietor event management system so that we can leverage our existing investment. Also let me know overall OTRS integration capabilities with all kind of systems like oracle financials, SAP, HR systems etc? Thanks for the help!! Regards Sudhir Garg