Reverse engineer windows application

We're using a particular windows software. There is a feature to import/export a toolset.
We need to manipulate/generate tools on our own externally. The data in the exported file is saved as a XML, but some properties are encrypted.

We need someone who can do kind of a reverse engineering. The goal is, that we can generate a toolchest externally in a C# application, encrypt it like it is encrypted in the software, so that we can import it.