Warning, this is a very loose guide to make some clumsy customs effects to buildings (like barracks increasing training time). By this time they don't work in a proper way. If I get help from the powers of modding or other folks like me then I'll update it.

Install the converter:
http://www.twcenter.net/forums/showthread.php?t=438386

Then, with the PFM (http://www.twcenter.net/forums/showthread.php?t=433370) extract the effect_bonus_value_unit_record_junctions_tables table, from the folder DB.

Then the tricky part, with the converter, you have to convert the DB file to Tsv. Then open the Tsv, you can do it with notepad, but I find that is a lot easer with wordpad.

If you open it with excel or calc you can see the file have three columns, the first one have the kind of value you want to change, i.e.:
armour_mod
melee_attack_mod
morale_mod
accuracy_mod
melee_defence_mod
And in your case you can add the value
charge_mod

The second is the name of the value on the rest of the values (the one you will be using on the effects and building effect and table.


The third one is the name on the unit affected for this value. I'm uploading an example for you to see it, here it is:http://www.megaupload.com/?d=XE38MNGR
I added some accuracy and melee effects, but the most noticeable is the charge bonus for all yari garys at the bottom.

Once you are done here you have to use the converter again to change it back to the db format. And there you have to upload it on your mod pack file.

Now only one thing is pending, you have to include and/or open the effect table on the db file on your mod. There you have to clone one of the lines and on the clone change the name of the effect, and that's it, you are good to go then. I always try to clone a effect similar to the one I'm adding, I.e. for the gary accuracy effect I cloned the already existent samurai accuracy one.