How to change the default theme in custom ROMs

Some people asked me how I change the default theme of my cooked ROMs. So, I decided to make a guide to it.
It's not a difficult thing, but you need to do it carefully, because you can screw the entire ROM with a wrong or missing line.

So, the method step-by-step:

Unpack the needed theme's CAB file (create an OEM package from it)
Go into the .tsk file of the theme with Total Commander (on PC) and open the _setup.xml.
Copy the content from the "<characteristic type="Registry">" line to the end (I presume, the file operation commands in the beggining of the file. If not, then you need to filter it out.).
Create the file "mxipcold_wpc_3.provxml". (That's the default theme's filename in the ROMs of the O2)
Paste the above mentioned lines to it and put the line "<wap-provisioningdoc>" to the very beggining. (the end of the file needs to "</wap-provisioningdoc>".

Put this code between the "<characteristic type="Registry">" and the pasted codes (replace the YourTheme.tsk with the name of the .tsk you want to apply):

		<characteristic type="HKCU\Software\Microsoft\Today">
			<parm name="Skin" value="\windows\YouTheme.tsk" datatype="string"/>
			<parm name="UseStartImage" value="1" datatype="integer"/>
			<parm name="DPI" value="192" datatype="integer"/>
			<parm name="MultiColorThemeEnabled" value="1" datatype="integer"/>
		</characteristic>
		<characteristic type="HKCU\Software\Microsoft\Today\YourTheme.tsk">
			<parm name="COLOR_TITLEFLATCENTER" value="0" datatype="integer"/>
			<parm name="COLOR_SOFTKEYFLATCENTER" value="0" datatype="integer"/>
		</characteristic>

Form the code, to see there's not missing any "</characteristic>" or anything.
If the theme is using images, and the path is not "\Windows\anything.png" then change it to that.
Save the file "mxipcold_wpc_3.provxml" and copy to the OEMApps folder (overwrite the original, but make a backup from it, before this).
Delete everything from the first created OEM package's initflash.txt
Optional: Change the "false" to "true" in the option.xml of the OEM package to make it checked by default in BuildOS.
Put the OEM package to the OEM folder
Cook and flash the ROM.

If you have any questions, feel free to ask.