I have a form that starts with a questionnaire and uses the information
in the questionnaire part to create a letter. For example The
questionnaire asks the name of the customer in a text form field, the
age of the customer in a text form field and I was trying to use check
boxes to add other items in the list but noted that the check boxes
cannot be used in cross references. For example:

Name: [Text Box Field 'Name']
Age: [Text Box Field 'Age']

Modes of transportation:  [ ]Car [ ]Airplane [ ]Train  [ ]Camel [ ]Horse
 [ ]Motorcycle.

Using bookmarks and cross references I would like the letter to read:

My client John Doe who is 20 years old uses the following modes of
transportation: Airplane, Train and Camel.

I have no problem with the first part of the letter getting the name and
age into the form, but how can I get only those modes of transportation
into the form letter that the person who fills out the form checks?

Text Field Boxes, Drop Down boxes etc are easy, but is there a way to do
the same thing with check boxes and if not what other way can be used to
get the same results?