Some newer Mio devices don't see the card until after reinsert.
To avoid this you can mount card : Settings - Storage Manager - Select SD Card ( option 2 ) - Properties - Mount .
I automatized this with MortScript.
Unrar and copy folder on My Flash Disk.
You can launch this script from unlock script or you can include it's content into unlock script.
Tested on Mio S 605 .