[html-formfu] Anyway to handle undef/0/1 Radiogroup

[Hu Hailin]

Hi,

===============
- type: Radiogroup
  name: invitation
  options:
  - [ ~, 'do nothing']
  - [ 0, 'refuse']
  - [ 1, 'accept']
===============

I tried to use a nullable db column to store such a status above and I
have trouble in filling a NULL value from db into form back properly.
The option whose value is ~( or '' ) will not be set checked="checked".

Any advice or workaround?

Thanks.
-- 
islue