How to add Extend SRA004 OData service for Extra field in Travel Request

Hello Gurus,

I am trying to enhance “FIN_TR_CRE” and extend “SRA004” Odata service by redefining it in a custom service but somehow system remove the structure for Entity type ‘Travel’. Now I have to add custom Entity type to update my Z table. But I am unable to understand following points.

• 1.System doesn’t give me my methods for my Entity type
• 2.How to call my entity type in data model from Fiori side
• 3.How I will get Trip id once I will achieve first 2 points.