GAAP vs IFRS and 4-4-5 vs Calendar Date Pattern

Does anyone have any experience with legal reporting for Latin America, which requires a calendar date pattern vs. 4-4-5 fiscal date pattern?   The issue is how to report using IFRS standards, as well as GAAP, when the company is on a 4-4-5 date pattern.  Do you set up a second company on a different date pattern or for doing GAAP adjustments or do you use a second ledger type? 

If you use one company and get IFRS from the F0911 detail (based on GL date), how do you manage accruals when the calendar month-end is before the fiscal period-end and the reversing entry ends up in the same period?  Do you just make another adjustment?