2007-01-01 Opening balances
  Assets:Cash         10.00 EUR
  Equity:Opening balances

2008-01-01 Buy 5.00 GBP
  Assets:Cash               5.00 GBP @ 1.4 EUR
  Assets:Checking

2009-01-01 Sell 5.00 GBP for 7.50 EUR that I bought for 7.00 EUR
 Assets:Cash                       -5.00 GBP {=1.4 EUR} @ 1.5 EUR
 Assets:Checking                     7.50 EUR
 Income:Gain

P 2009-02-01 00:00:00 GBP 1.5 EUR

test reg
07-Jan-01 Opening balances      Assets:Cash               10.00 EUR    10.00 EUR
                                Equit:Opening balances   -10.00 EUR            0
08-Jan-01 Buy 5.00 GBP          Assets:Cash                5.00 GBP     5.00 GBP
                                Assets:Checking           -7.00 EUR    -7.00 EUR
                                                                        5.00 GBP
09-Jan-01 Sell 5.00 GBP for 7.. Assets:Cash            -5.00 GBP {=1.40 EUR}    -7.00 EUR
                                                                        5.00 GBP
                                                           -5.00 GBP {=1.40 EUR}
                                Assets:Checking            7.50 EUR     0.50 EUR
                                                                        5.00 GBP
                                                           -5.00 GBP {=1.40 EUR}
                                Income:Gain               -0.50 EUR     5.00 GBP
                                                           -5.00 GBP {=1.40 EUR}
end test