Callouts : Show only certain part of a meta-property as text of callouts

Hi guys,

Whenever creating illustrations with callouts the BOM-IDs that are shown are not correct compared to an other source of information that I'm using. In the "Instance Name"-meta-property of the parts, the correct position number is available. So of course, I could use that meta-property instead as callout text.

Here is my problem:  in front of that correct number in the "Instance Name"-meta-property there's some text that I need to remove. I've attached an image to make it a little bit more clear: in the red box the text of the callout is currently "Meta.InstanceName". I would like to only show the last number(s) of that meta-property. So "88694 pos 08" should be "8" or maybe even "08".

How can I adjust the text of the callout so I refer to the meta-property BUT with some certain parts removed? My suggestion would be to maybe use a text string similar to the formula you would use in Microsoft Excel: =right(A2, 2). But "A2" would be "InstanceName" in this case. That doesn't work tho.

Any suggestions?

Note: I need to apply this to a lot of illustrations and callouts so manually adjusting them isn't an option.