One time revaluation of OTI with amortization

Hello experts -

I have a business requirement to perform a one time revaluation of our debt instruments including performing and amortization to expense of the FMV adjustments.

We are on ECC6 without any EHP and using the money market area.

As an example:

01/01/2013 - FMV as received by business - 90K

01/01/2013 - Carrying  value of debt (sum of structure flows) 100K

02/01/2013 - Structure pmt - 10K

03/01/2013 - Structure pmt - 30K

04/01/2013 - Structure pmt - 40K

05/01/2013 - Structure pmt - 20K

FIMA_APR_Calculate can be used to back into the intererest rate - 48.042%

The users want to amortize the FMV difference to expense as follows -

02/01/2013 - (90,000*48.042%*30/360) = 3,603.15

03/01/2013 - (90,000-(10,000 - 3603.15))*48.042%*30/360 = 3,347.05

04/01/2013 - (90,000 - (10,000 - 3603.15) - (30,000 - 3347.05))848.042%*30/360 = 2,280.00

Is there a standard function to use in the money market area to achieve this result?

I appreciate any help.