Biztalk comes with a fair amount of functoids included; recently I encountered a situation where the function I needed wasn't available in the collection of functoids. Although I haven't created any custom functoids for the old versions, I must say that creating a functoid for BTS 2004 is very simple.
The function I was looking for, was being able to apply a Regular Expression to a value and to return the first match. The actual code that provides this function is very simple, but it might be a nice starting point for creating your own functoids. The sources can be found here: ![RegExFunctoids.zip](http://www.alexkeizer.nl/assets/RegExFunctoids.zip) (16,59 KB)