Disable custom field in SUS PO / POR item level

HI all,

We are using SRM 5.0, ECC6.0 and ECS scenario.

We have a requirement where a custom field in SUS portal has to be disabled for a certain condition.

I have checked for BADIs which could help me achieve this but none are available.

BADIs such as CUF BADI are not getting called while navigating through SUS PO and POR.

Please let us know if there are other ways through which we can achieve this.

Regards

Kishan