I would not carry it with the broken parts. Once they are replaced, I would not hesitate to carry it again. To get the replacement parts, you will probably have to contact HK. I tried to find the part at some other places, but couldn't. This is their contact info:
Heckler & Koch
Commercial and Civilian Sales
5675 Transport Blvd. Suite 200
Columbus, GA 31907 USA
Tel: (706) 568-1906
Fax: (706) 568-9151
Email:
cs@hk-usa.com