What's the best way?

I have had a requirement come across my desk to search for and identify particular information within our cases in E9 (9.05.701 sql 64).

The customization needs to display a message allowing the user to acknowledge it, with acknowledgement information being stored in the database for reporting purposes.

I have done some investigation and thought I may be able to do a BPM, on the update method to get things moving, I briefly considered using ABL, but it appears it is fairly limited in functions with regards to wildcard searches (I think it is MATCHES allows * and . wildcards), I need to identify numeric strings with a certain length of character. Being from a SQL background I would have used something like the LIKE Clause with [0-9]0-9]....etc.

I thought that using C# and regex would be the way to go and hopefully make it E10 transportable.Possibly using the "invoke a .NET method" and use the BPM server, or am I missing the point of this BPM Action?
What are peoples opinion?

Kind Regards
Simon Hall