Searching for a combination of chars (i.e. -20) in an integer attribute?

We have a search panel where the user can search for "elements" based on certain criteria (parent, ID etc). One of these criteria is ElementID. ElementID is stored as an integer in the entity but the users now wants to enter i.e. '20' as a criteria in the Search Panel and get all Elements with an ElementID that contains '20', returned to them in a list. Any suggestions? FYI; I can not change the attribute to a string
1 answers

It's clearly been a mistake to make this field an Integer.

I can't think of a reason why you can't change it to a String now, but since you can't;

You can create a new Field that is a String, and in it store the same value as a String. Let the user use this field for searching.