Doepfer

I am planning to remove the tapped rails in my Doepfer suitcase and 
replace them with slide nuts. I looked at the Proma Systro page and it 
looks like ones that will fit are DIN 562 M3. Is this correct? Also, if 
anyone knows of US distributors for these parts, please let me know. 
Mdmetric.com is one that I found.

-nicholas