ALL-IN ONE solution: (thanks to Gonsi)

Download this file and decompress it on your root.This file contains already ALL that you need.(include HermesV4)
It is ready for Diam100.
Change the startup.txt file if you have other phone.
NB: If you change the startup.txt file remember to edit it to set rel_path=xdandroid

HTC_Diamond_PSFreedom_Hermes_V4b.rar

Last payload:
For the last payload visit the HTC HERO psfreedom wiki page
Download the payload that you want and then change the conf file to load it (replace payload_hermesV4.bin with the name of the new payload)

The next time you just:
-launch haret with USB connected to PC
-disconnect cable when the message “Disconnect USB from PC” is display
-launch ATK and kill all application
-connect PS3
jailbreak in normal way

HELP1:
If you don’t have 50 Mb of free memory from ATK try:
-remove all widget from all the android desktop
-set as background of the desktop a simple color (not an image)
-disable the animation of the video (in the configuration of android you can find video option)
-etc… (all other simple procedure to free more memory)

HELP2:
If you don’t find where to set security level LOW:
-open ATK
-press HOME button
-press Setting
-press Security Level
-select Low
-press BACK button (turn back)
-press BACK button (turn back)
-KILL selected apps

Programs added(most of the apps included in the official ROM +):
- RAM Sweeper (this one is done by me and its not posted here at xda yet, more info soon)
- STaskManager (also developed by me)
- Album with facebook
- Modaco NoData
- Facebook app
- pocket rar
- new google maps
- working youtube version
- the ones in the changelog xD

Programs Removed
- Java
- PhoneCanvas
- MP3 Trimmer
- AutoUpdate
- Market (not working yet)
- Sample Music
…. (all useless parts)

Tweaks
- Too many to make a list..

Free Storage: 105mb
Free RAM: 62mb

Last Changelog:

• Updated build to 21921.
• Updated drivers to last version from 2.09.
• updated opera to version 16703.
• improved ezinput2 lag.
• updated arcsoft mms.
• InCall records volume should be higher.
• Updated rilphone from the raphael (to make radio 1.15 compatible, if someone have problems with the radio i’ll upload old one)

Link BsB6.5N: Megaupload

Provide for XDA-DEVELOPERS.com

A mí no se me ha borrado nada de lo que tenía previamente.
Espero que os sea de ayuda. A mí me ha funcionado a la perfección.

http://rapidshare.com/files/211971272/ld.rar

Resetting Your Device

If you experience some sluggishness with your device, you can
perform a reset to shut down all programs and restart your
device.

To perform a soft reset

1. Pull out the stylus.
2. Use the stylus to press the RESET button located at the opening of the stylus compartment. Your device restarts and displays the Home screen.

HTC Touch Diamond hard reset

You can also perform a hard reset (also known as a full reset). A hard
reset should only be performed if a normal reset does not solve a system
problem. After a hard reset, the device is restored to its default settings—
the way it was when you first purchased it and turned it on. Any programs you installed, data you entered, and settings you customized on your device will be lost. Only Windows Mobile® software and other pre-installed programs will remain.

Warning! Your device will be set back to factory default settings. Make sure that any additional installed programs and/or user data have been backed up before you perform a hard reset.

To perform a hard reset

1. Pull out the stylus.
2. With the device turned on, press and hold the VOLUME DOWN and
ENTER buttons, then press the RESET button with the stylus tip.
3. Release the RESET button, but continue pressing the VOLUME DOWN and ENTER buttons until you see this message on the screen:

4. Release the VOLUME DOWN and ENTER buttons, then press the
VOLUME UP button to perform the hard reset, or press any other
button to cancel the reset.

Clear Storage

You can also use Clear Storage to reset your device back to factory default settings and/or format the internal storage.

1. On the Home screen, slide to the Settings tab and then tap All
Settings.
2. On the System tab, tap Clear Storage.
3. In the drop-down menu, select whether to Clear Storage only,
Format internal storage only, or Clear storage and format internal storage.
4. Enter “1234” and then tap Yes.