Sending mails to a restricted DL from a Public Folder

Hi gents,

We're currently working with an Exch 2010 instance and got a request for which we can't find a solution.

We've a DL which is senders restricted to avoid the overflow of mails due to the amount of users in this DL.

Here's the challenge :

We have a user which is member of a public folder and she wants to send mails on behalf of that PF to the restricted DL.

How can we arrange this access as she doesn't need to send the mail from her private address ?

Thanks in advance for your help.