presumably the template box does have some sort of limit. If so, just split it over multiple routines, and check that the system calls them one after the other.
If you have a "large block" of HTML though, I'd be tempted to put it in a text file, in the web folder, call it say "waffle.htm" and then include it in the netwebpage as
<!-- Net:f:waffle.htm -->
That way you can edit the text outside the app if you like.
(note you're just pasting the "content" of HTML in the waffle.htm, not a whole page - ie just the "inside the body bit")
Cheers
Bruce