How to configure custom ID column names (e.g., id_user, id_session) ?

export const auth = betterAuth({
    database: drizzleAdapter(db, {
        provider: "pg",
        schema: schema,
    }),
    // ... other configurations ...

    /* BA Core schema change */
    user: {
        fields: {
            // Trying to map the internal 'id' field to my 'id_user' column
            id_user: "id_user" // <-- This is where I'm attempting the configuration
        },
        additionalFields: {
            first_name: {
                type: "string",
                required: true,
            },
        },
    },
});

Object literal may only specify known properties, and 'id_user' does not exist in type 'Partial<Record<"name" | "email" | "emailVerified" | "createdAt" | "updatedAt" | "image", string>>'.