Split cell after a certain string

I have emails in a column and I want to split each cell (email) into a body and a metadata column. So far the Cell Splitter node did nothing. I have tried to split the emails at empty lines or certain characters and I always get the same, the copy of the original text without splitting. Is there another way to split a string or better, a document? Here’s an example of an email (it’s in public domain, from the ‘ENRON Corpus’) that I would like to split after ‘X-filename:…’ :

Message-ID: <26127350.1075840042651.JavaMail.evans@thyme>
Date: Wed, 23 Jan 2002 17:02:42 -0800 (PST)
From: no.address@enron.com
Subject: Copier Commitment Information Requested
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-From: Enron Corporate Administrative Services@ENRON
X-To: All Enron Employees North America@ENRON
X-cc: 
X-bcc: 
X-Folder: \ExMerge - Slinger, Ryan\Deleted Items
X-Origin: SLINGER-R
X-FileName: 

Houston Offices Bankrupt and Non-Bankrupt Business Units:
If you own, lease, rent, or receive invoices for copiers or have questions regarding copiers 
Please call Harry Grubbs at 713-853-5417, or harry.grubbs@enron.com.


All Bankrupt entities outside Houston, or other Offices outside Houston that are closing:
If you own, lease, rent, or receive invoices for copiers or have questions regarding copiers 
Please contact Paula Corey at 713-853-9948, or paula.corey@enron.com.


Non-Bankrupt Entities Outside Houston:
Please call Harry Grubbs at 713-853-5417, or harry.grubbs@enron.com.