Overriding select widget template for 'just one place'

Plone Support Add-on Development
1

I need to override the template.pt for one of the classes of collective themefragments.

class IFragmentTile(model.Schema):
"""Generic theme fragment tile"""

fragment = schema.Choice(
    title=_(u'Theme fragment'),
    vocabulary='collective.themefragments.tiles',
)

I need to override the select widget 'just for IFragmentTile ?'.

This is the code that works (but register it for all Choice Fields)

 <z3c:widgetTemplate
  mode="input"
  widget="z3c.form.browser.select.SelectWidget"
  layer="z3c.form.interfaces.IFormLayer"
  template="imagepicker_input.pt" />

is it possible to use something like (ps: tested, did not work)

for="collective.themingfragments.IFragmentTile"  ?