Manually Re-attaching Proxies

I'm not sure is this a bug or just my Premiere problem? (Maybe my setting is wrong?) Everytime I wanted to attach proxies file which is not created by Media Encorder (Example using camera proxy) OR when I accidently close the Premiere Pro project file while Media Encorder still runing the proxies, when open back the project file in Premiere Pro, proxies are all offline. Try to re-attaching the proxies file but it doesn't appear in the Premiere Pro pop up window (Proxy is ald completed render from Media Encoder). Whyyy??? I notice it could because of the different file type/file name that cause my Premiere Pro couldn't recognise the proxy file...How can I fix this?