I see, ... but you have here something to start (did you tested the command PLACETEXT or adapted the C# code to suit your needs?), the only other problem I see, is that when you end up having an area, where the command boundary or bpoly, not capable to generate the closed area, then you will require to do it manually or make your own boundary generator, when bpoly fails, will see if a solution is provided...
[edited by me]