Hi Yury,
There is an untidy but effective way of entering FX movements on foreign accounts manually.
If for example, our base currency is GBP, and we have a USD account which we wished to revalue at £17 higher than previously, enter the following set of transactions: -
Using money > money in enter a transfer of $1 / £18 from the GBP denominated current account to the USD account
Using money > money out enter a transfer of $1 / £1 from the USD account to the GBP account.
Using money > money in enter a transaction coded to profit or loss on foreign exchange to the GBP account of £17