Hi Indra,
The changes for IW32 are being captured in CDHDR and CDPOS only.
You can verify this from IW32 as follows:
go to tcode IW32 -> provide any service order -> display -> (top menu) EXTRAS -> DOCUMENTS OF ORDER -> CHANGES
Above will give you all the details of changes to the order in ALV format.
The first column is of 'Object Value'.
You can then go to SE16 and in table CDPOS and provide this Object Value in the CDPOS object value field and you will get all the same entries in the change log.
Please let me know if you have any questions.
Thanks
Amit