Change Classification Hierarchy data at Item Portfolio

Dear Gurus;

We developed a program to change/modify Classification Hierarchy data from Item Portfolio, but we have a problem, because we found that the method to change data are private and they doesn't call it from Z program.

This method MODIFY_ASSIGNMENT it's private from /RPM/CL_BUCKET_API class.

Someone has found another solution to change/modify classification hierarchy data?

Thank you,

Regards,

Mariano