Question has been posted and answered before...
http://forum.ppcgeeks.com/showthread...ext+rom&page=2
You will need to hide the ext rom, for it to use your regular sd card to save attachments.
To do that change this reg entry using a reg editor and soft reset.
hide ext rom
[HKEY_LOCAL_MACHINE\System\StorageManager\Profiles\ TRUEFFS_DOC1]
"MountHidden"=dword:00000001
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