Adding New Text into mission Briefing...how do I do it?

[General Crum]

Hey everyone, 

I've been working on my own campaign where I have been adding the mercenaries (working with other player to make more of a 2v1 situation). The issue I am having is I want to add some text into each mission briefing, but every time I change it / add new words It doesn't save, even when I have manually saved it. 

I am currently using gruntmod, and using the UITableEditorV0.3 to open the text.uib file. This opens fine, and I can find the first atreides mission AM2Text2. When I try to change this is doesnt save. What am I doing wrong, what else am I missing. 

All I want to add is "The Mercenaries may join our cause, but are wary of us, succeed at all costs and keep their 5 soldiers alive".

Cheers

General out.