Using Exec-Program-Wait for MOTP (mobile OTP) with MSCHAPv2

[Fabiano]

Hello,

Does anyone know where I can find some information on how to use the 
following in freeradius ?
I have an external shell script which awaits arguments (username, clear 
password, and other arguments) and returns an answer for validation.
The problem is that I cannot find any lead on how to do this while using 
MSCHAPv2...
And I am not sure how to do this with Exec-Program-Wait.

Is this possible without rewriting the module in C ?
Is there any way to have the cleartext password sent to the external 
script ?

Thanks a lot

Fab