Not sure if this it too late to help, but I had a lot of concern about monitoring my work email via N810/Diablo because I get on the order of 100MB a week. After a fresh boot, I copied ~/.modest to the internal flash, removed ~/.modest, then did a symbolic link to the directory on the internal flash. This seems to be working. If you did that before the import that would keep you from filling internal memory.

(had to do the same for roadmap - why don't these apps with large memory requirements do this by default?)