Yes: you can export your mind maps from SimpleMind Touch eXpress v 1.08 through v1.2.1 to full SimpleMind iPhone and iPad versions v 1.2.1.

In SimpleMind Touch eXpress:
For every mind map you want to transfer to the full version, press the button in the left bottom corner and then use "Export to SimpleMind' to transfer the mind map to the SimpleMind Touch full edition.

Note: this is no longer available in SimpleMind Touch Express v.1.3.0. After updating to the full version through In App purchase you keep on working with the same Mind Maps you created with the free version.