Mapping is not available for Keyfigure 0CRM_NUMIN

Dear Experts,

While populating data to DSO 0CRM_CT_I (Customer Contact: Inbound) it is observed that the mapping is not available for keyfigure 0CRM_NUMIN between datasource [0CRM_CONTACT_IN] and DSO 0CRM_CT_I.

Could some one please guide how to populate data for the keyfigure 0CRM_NUMIN so that I can map appropriate source filed/fields for the same.

Thanks,

Khader