To my knowledge , the following collection of Khmer Unicode are compatible with Photoshop CS3 or higher. I have no information for any version that is lower than CS3. There is no especial setting or configuration with this collection. All you have to do is switch to one of these fonts and type it normal as you normally did with the regular Khmer Unicode. It’s will display the words that you type as a whole instead of seeing the characters and vowels got separate. Click here to download.
1. For Windows Vista, Windows 7 or Windows 8, simply download and extract the zip file to your desktop. Open the extracted files, highlight all the fonts and simply right click on the mouse and click install.
2. For Windows XP, Click Start… Control Panel. On the right-hand-side, click on Switch to Classic View. Click on Fonts icon.
Go to File and click Install New Fonts…
In your C:/ folder, click Document and Setting
Choose (your user name)
If you extract your file and save on your desktop, click Desktop and find your folder that contain the fonts. After that you will see all the list of fonts contain in that folder under List of Fonts field. Click Select All… and click OK to install.
Sample on Photoshop CS3 Extended