Hello Clem,
The only way to do that, for a new system without any data entered would be to delete all fiscal settings.
To do that, go to Nominal ledger module>>Settings>Fiscal years>>
1. Delete all lines and save
2. Open again the setting, write on line 7 code 2014, start>01/03/2014, end> 28/02/2015, delete the empty lines above, Save
3. Add the other years later on
If you have already entered some data, it is not possible to edit, only to add new fiscal years.
Regards,
Hansaworld support