Macro trigger in CRM based on custom field

Hi

I've looked info triggering a dialog when a sale is saved if a certain custom field is enabled on the company card.

Example:

Company A has custom checkbox field "NDA" enabled

Creating a sale and pressing Save for Company A should show a dialog with the text "Remember to attach NDA to quote" if the NDA checkbox field is enabled.

However, I cannot dig into the custom fields when creating macros - is that possible or is there a secret trick to this (apart from writing scripts)

thank you in advance

Ole