For discussions related to creating custom items, see:

http://www.empirisoft.com/support/sh...ad.php?p=12953

However for this purpose, you might simply get by using the <specify> function in your questionnaire. e.g., in the case above, you would enter this option in your scale response:

Other (please specify) <specify>

For more detail, see also:
http://www.empirisoft.com/medialab/h...textlabels.htm