/user/register page Redhen contacts block title not translated/customizable

Hi.
I've d7, Redhen and Logintoboggan installed.
When a new user registers, the /user/register page displays a form with :
- username/password selection
- Redhen contact fields (name/middle name/first name/street address/...)
- a couple fields that we added to drupal users.
The site is in french (english install, then add french, set french as main language and disable english).

The redhen contact fields section is in an expanded, noncollapsible block, and has title 'Volontaire contact information'.
'Volontaire' is the system name of our redhen persons contacts.

First issue : the redhen contact type was later renamed to 'person' but the system name was kept as 'volontaire' so as not to disrupt all existing views, relations, etc. The registration form should not display the system name of the contact type, but rather the display name ('person', not 'volontaire')

Second issue: the string 'contact information' is not translated, nor customisable.

We should be be able to either hide the 'Volontaire contact information' fieldset legend altogether, or to be able to translate and/or edit it.
I looked in Redhen module and templates, as well as in drupal user and contact and logintoboggan and could not find where this is displayed. It looks like it comes from Redhen as it's the fieldset that was defined for Redhen contacts.