Yep, the problem seems to be that if we don’t have a Payment Type with Customer Account as the Credit transaction, then the value will always be displayed as the ZERO value.
Because I am sometimes using the Customer Account for expense payouts and refunds, I have the Customer Account as the Debit transaction, but this entire set-up does not currently work, SambaPOS just ignores the payment altogether. Emre has said this will be resolved on the next relase, @Emre, is it also possible to have the Entity Balance displayed correctly when the Customer Account is either a Credit or Debit transaction?