AIF Inbound ports - adjustment of ledger services

I would like to adjust the standard ledger services that ship with standard AX because they do not include all the fields that I would like to Import into AX.
I need to know whether it is possible to make adjustments to this service and if so, how to realize those adjustments?
Hope somebody can help.

Yes, you can change standard document services - its just X++ code. First of all, ensure yourself that the fields you miss aren’t merely disabled in port’s configuration. Can you give us an example of a field you need and in which service?

You used the term “inbound port”, so I guess you’re using AX 2012 - is it correct? (Please always attach a tag with your version of AX.)