How to get nHibernate, composite-id and INNER JOIN/WHERE IN together?

Question

NHibernate

There is such a TSQL

SELECT Data.*
FROM [currrates_data].[dbo].[CashExchangeRates] Data
INNER JOIN (
    	SELECT
        [FinancialInstitutionCountryCode],
        [FinancialInstitutionName],
        [BaseCurrency],
        [QuoteCurrency],
        MAX([Timestamp]) AS [Timestamp]
    	FROM [currrates_data].[dbo].[CashExchangeRates]
    	GROUP BY
        [FinancialInstitutionCountryCode]
        	[FinancialInstitutionName]
        	[BaseCurrency]
          [QuoteCurrency]) Filter
ON
    	[Data].[FinancialInstitutionCountryCode] = [Filter].[FinancialInstitutionCountryCode] AND
    	[Data].[FinancialInstitutionName] = [Filter].[FinancialInstitutionName] AND
    	[Data].[BaseCurrency] = [Filter].[BaseCurrency] AND
    	[Data].[QuoteCurrency] = [Filter].[QuoteCurrency] AND
    	[Data].[Timestamp] = [Filter].[Timestamp]

How to translate this to nHibernate? It won't work through SubQuery, because CashExchangeRate has a composite-id (FinancialInstitutionCountryCode, FinancialInstitutionName, BaseCurrency, QuoteCurrency, Timestamp) which won't work through WHERE IN.
What was found: nHibernate does not support JOIN on unrelated entities, that is, JOIN on the same table cannot be done.
I see 2 options: change the structure and enter a surrogate ID (record number chtoli), or write it in raw SQL.