Account Type "Employee" has been added for General Journals not so long ago, but there isn't a possibility to post line with such type and Currency Code:

Validation Results

The value of the Currency Code field must be empty. General journal lines in foreign currency are not supported for Employee account type.

We need this possibility.

Previously for the purposes of employee accounting, Account Type Vendor had been used, where posting with Currency Code is available.

Hint: just copy and paste all code that is responsible for currency posting for the Vendor type, then replace word Vendor with Employee ))