Has anyone tried to create custom fields similar to the Ship To Select and Ship To fields on Sales Order? The reason why we need this is that there are three addresses shown in our invoice. One is billing, second is shipping and third is a special one. I'd like to be able to have a list field that sources the stored address labels from the customer selected in the SO then show the whole address in another field (similar to how the Ship To address works on SO). I will then use that 'another field' with the whole address on the advanced pdf. I was able to achieve the field that shows the address label but not other field with the whole address.

I have done similar although in my use the Fields were on a Case record.

If you wish to select say the address label from a custom list field, you'll need a script to actually source and post the address to the transaction form