Extract email body

Hello,

I have the requirement for a data migration project to extract the email body from SAP CRM. I've found some relevant programs: class CL_CRM_EMAIL_UTILITY_BASE, method GET_MAIL_DATA_FROM_SO or FM SO_OBJECT_GET_CONTENT. However, these programs require the inputfields OBJTYP, OBJYR and OBJNO from the SOOD-table.

How do I link the functional email ID with the SOOD table?