Perform a simple validation of a custom field in AI_CRM_ORDER_SAVE

Hello,

I want to perform a custom validation of a custom field just before saving my order.

I found out I should do this in the CHECK_BEFORE_SAVE method of the AI_CRM_ORDER_SAVE Badi, but I cannot figure out how to get the value entered in my custom field.

Can anyone point me in the right direction?

Thanks in advance!

Regards,

Tim.