Creation of Account Types / Balance Sheet for Romania negative values

The Romanian Balance Sheet example:
1. Cheltuieli de constituire (ct. 201 - 2801)
This is in the assets node.
Account 201 is asset, account 2801 is liability.

There are other examples:
3. Concesiuni, brevete, licenţe, mărci comerciale, drepturi şi active similare şi alte imobilizări necorporale (ct. 205 + 208 - 2805 - 2808 - 2905 - 2908)
Here all the account codes that have minus in front of them are liabilities.

On page 19

So each account has one type. The type is either an asset or a liability, or it also has a debit type.

I do not understand how they mix both assets and liabilities inside the balance sheet, for an entry that should be one account type in Tryton.

I guess it means that if the balance is a credit it goes in a specific type and if the balance is debit it goes in a different type.
This can be managed with the debit_type and credit_type in Tryton.