you may want to take a look at Infor's U7850B US "Writers Guide and Reference for Infor XML 6.4 Help Customization". You can download the PDF via Infor365.com DocLink.
I've just recently "discovered" this guide myself.
Basic help-customization (changing existing help-texts) in LN can be done by enabling help-customization in the users webtop-profile. This will add a "customize" button in the webhelp of the customized session.