If you need to change editor types after creating a BookVars file, you'll probably need to re-create the BookVars file from scratch. If you're sure there are no high-ASCII characters, you can just change the EditorType parameter (in the General section) accordingly (1=external editor; 0=internal editor). Before making this change, you may want to make a backup copy of the file.
If you have only one variable group, the easiest way to switch editors is to first verify that you have imported the latest variables into your Frame documents, then generate a new BookVars file (selecting the correct editor type).
If you have multiple variable groups, you will need to perform a series of import and generate operations, while copying and pasting the resulting groups into a new hand-build BookVars file. The following procedure described one possible method:
For example, if you have 4 groups, the Groups section could look like the following:
[Groups] Count=4 1=GroupOne 2=GroupTwo 3=GroupThree 4=GroupFour