Ace for Archlord Data Editor.
wsv for teaching how to use .png files without .dat
Archlord Data Editor:

Data.dat and Reference.dat which includes ui textures(from justac):

New Client ui_1024x768.ini(from justac):

Ini Decrypt/Rescrypt:

Some parametres from decrypted ini file and what they do:
[[UI_NAME]] // Name of the ui. Ex: [UI_SKILL]
CtrlDisplay=1: [String] // UI Text. Ex: CtrlDisplay=1:Exit
Pos=[x],[y] // Position of ui button or w/e it is. Ex: Pos=102,130
Size=[width],[height] // Size of ui button or w/e it is. Ex: Size=16,16
Texture=[1,2,3,...]: [path_to_texture] // Path to texture. Will be explained detailed later on.
CtrlName=[UNIQUE_CTRL_NAME] // Name of the ctrl. Most cases CONTROL_XXX but sometimes it's specific like CONTROL_UpgradeTab3
There are a lot more parametres but these are the ones i could gave a meaning for now.
Now i'll try to explain how to change a whole [[UI_NAME]] with new texture files.
1) Export all textures from data.dat file using Ace's data editor. Move them to the following folder: [path_to_client]/texture/ui/[folder_name_of_your_choice]
2) Decrypt both(your ini file and the ini file from new client, in our case, justac) ini files in seperate directories.
3) Open decrypted ini file from new client. Find the specific [[UI_NAME]] you want to replace. Copy from [[UI_NAME]](included) to EnumName=0(included). Open decrypted ini file from old client. Find the same [[UI_NAME]] and select as the same then paste.
4a) Replace all Texture=x: with Texture=x:[folder_name_of_your_choice]/
4b) Not in all [[UI_NAME]]'s. Just the one you replaced with the code from new ini.
5) Save and close the old ini file. Rescrypt it. Rename it as ui_1024x768.ini and put it to your client/ini directory.
6) Launch the game and enjoy
P.S. Following [[UI_NAME]]'s have more than three resolution options. Make sure you replace them all.
[UI_LG_IDPASSWORD] / [UI_LG_IDPASSWORD_1280] / [UI_LG_IDPASSWORD_1600]
[UI_LG_2D] / [UI_LG_2D_1280] / [UI_LG_2D_1600]
[UI_LG_CHARCREATE] / [UI_LG_CHARCREATE_1280] / [UI_LG_CHARCREATE_1600]
[UI_LG_CHARSELECT] / [UI_LG_CHARSELECT_1200] / [UI_LG_CHARSELECT_1600]
[UI_LG_2D_Back] / [UI_LG_2D_Back_1280] / [UI_LG_2D_Back_1600]
[UI_SelectServer] / [UI_SelectServer_1280] / [UI_SelectServer_160]
[UI_CharInfo] / [UI_CharInfo_1280] / [UI_CharInfo_1600]
Some screenshots from my ep1/2 test server(arisen):

P.S. 2
You can add new items to UI. Just copy one of the Elements from CtrlName= to CtrlType=1:. and paste it to next line and change the CONTROL_XXX to anything you want(care to not name it one of the existing ones). Done






