Increase custom fields length

I followed the steps explained in this article without any success :

How to increase custom fields length to be more than 255 characters
http://galleryproject.org/node/50546

This article being quite old, does anybody know if this method is still accurate ?

Gallery version = 2.3.2 core 1.3.0.2
API = Core 7.54, Module 3.9, Theme 2.6, Embed 1.5
PHP version = 5.4.4 apache2handler
Webserver = Apache
Database = mysqli 5.5.25, lock.system=database
Toolkits = Exif, Gd, Thumbnail
Acceleration = none, none
Operating system = Darwin iTom.local 12.2.0 Darwin Kernel Version 12.2.0: Sat Aug 25 00:48:52 PDT 2012; root:xnu-2050.18.24~1/RELEASE_X86_64 x86_64
Default theme = matrix
gettext = enabled
Locale = fr_FR
Browser = Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_2) AppleWebKit/537.22 (KHTML, like Gecko) Chrome/25.0.1364.160 Safari/537.22
Rows in GalleryAccessMap table = 34
Rows in GalleryAccessSubscriberMap table = 2637
Rows in GalleryUser table = 5
Rows in GalleryItem table = 2635
Rows in GalleryAlbumItem table = 63
Rows in GalleryCacheMap table = 0

Thanks for your reply.

Yes I did.

I followed each step scrupulously :
1. DB change
2. Change Maps.inc (and .xml by the way)
3. Clear DB cache

Whenever I enter some text longer than 255 characters in a custom field through the site admin, it will be truncated to 255 characters after saving.

I can nonetheless enter some longer text through PHPMyAdmin, and retrieve it through the site admin.

This is weird.

Thank you. This mod is 7 years old. It seems it stopped working for some of us at some point.