Why can't I save Attachments with Astro File Manager?

Hi new to the forum here. I love Maildroid, switched from K9 due to issues with it. I tried to save some pics I recieved as attachements to the SD card. It only gives me the option to save as and then will not use my Astro File Manager app which I already have on my Droid X. It gives me three other file manager apps like AndExplorer and a couple of others to download to do it. It also will not just let me save as well. When I try to save, it gives me an error report. I really rather use Astro, why isn't this able to work with attachments? Can they make it an option on this?