SecSy allows users to define their own custom transformers to be used in simulation procedures. The procedure for this includes the following steps:

1. Write a custom transformer class.
2. Write a graphical frontend for parameter setting.
3. Include custom transformer in simulation directory.

A general prerequisite for defining custom transformers is the availability of prepared abstract classes for custom transformer definition either via downloading the SecSy source code from SVN or using the jar-version of SecSy and including it in your build path.