Hi,
barcharts should already work. No enhancements are required.
Without a sample file I can't reproduce the issue so I cannot solve the bug, please try to share your code/excel.
Anyway there is the possibility to use the "template" load/write for the charts, if you don't want to modify them.
This way is documented in the ZDEMO_EXCEL37 by setting the attribute excel->use_template = abap_true.
Please try if it works in this way