Tax category in GL Account master data?

Hi all,

We have maintained a tax code 'AA' into a GL master data - 'Tax category' field and untick 'posting without tax allowed' under 'Control Data' tab.

However, during payment posting (via transaction code F110) to that GL account, the tax code field was posted with blank and not defaulted to tax code 'AA'. The tax code was defaulted for that GL account if I post via transaction code FB60.

Appreciate if anyone can share with me the reason why and how to auto derive the tax code for a GL account during F110 posting?

Thanks in advance.

Regards,
May