I need to write an application, that gets called from the CRM UI. This application will use a RFC to call ECC to access a program and bring the data back to the RFC in CRM. I have the functiona modules working, but struggling with how to write the application in CRM. My thoughts was to create a BSP, but struggling with where to create my BSP. Should I create the BSP in the ABAP workbench or should I use the BSP component workbench, or does anyone have any other thoughts what to use to create my application?