You are correct that Mobile needs Number data to view a legend.
Here are some steps as a work around.
1. From FW Office, right click on the Variety Layer name from the Red Barn tab and select Copy. 2. Right click on the field name for same crop year enterprise and select Copy.
This will create a new layer called Variety Map Copy\
1. Right click on the new layer name and select Properties 2. Click the Add button type a description such as Variety number and select Number for the Type and click OK. 3. Display this new variety map copy layer as top layer. 4. Go to the Layers tab to the View box and highlight the attribute for the Variety. 5. Go to the Legend box and double left click on your first seed variety name. This places a cross hatch pattern on the areas for this one seed variety. Click the Edit Layer button. Right click on the mapping screen and select Properties. 6. Check the box for Variety Number. Enter a number (no letters) and click OK. 7. Go back to the Legend box and double left click on the next seed variety name. Right click on the mapping screen and select Properties again. Check the same box called Variety Name and enter another number and click OK. Repeat this step until all seed variety areas have been defined. 8. Click Save and close. Now back to the View box from the Layers tab and highlight your Attribute name called Variety Name. You should have a colored map showing these new numbers that were assigned.
Now export this layer as an AcrView Shape and take to computer running Mobile. Load this layer as a background and from the same Open window after the shape file has been opened and select the open button and select Legend, this time in the data item box you will have this new attribute for Variety Name you can setup a legend for.