[ZendTo] Problem with verify email for dropoff

[tibz]

Hello,

I have a problem when external users want to do a dropoff for internal 
person without being invited (self invitation).
During the process, they should receive a mail to confirm their 
identify, but this mail never arrived.

After troubleshooting, it appears that the zendto application is passing 
a bad address format during the SMTP transaction. Here are the logs from 
our Exchange hub:

2013-03-28T13:47:13.432Z,VMWHUB001\Open Relay,<,MAIL 
From:<Company.SecureFile.Beta.\<no-reply at company.tld\>> SIZE=1324,
2013-03-28T13:47:18.447Z,VMWHUB001\Open Relay,>,501 5.1.7 Invalid address,
2013-03-28T13:47:28.463Z,VMWHUB001\Open Relay,<,RSET,
2013-03-28T13:47:33.479Z,VMWHUB001\Open Relay,>,250 2.0.0 Resetting,

On zendto /var/log/maillog, we have :
Mar 28 14:47:18 zendto sendmail[28673]: r2SDl36x028670: r2SDlI6x028673: 
DSN: Data format error

And in the mail received by root:
    ----- Transcript of session follows -----
... while talking to smtp.erasme.ulb.ac.be.:
 >>> MAIL From:<Company.SecureFile.Beta.\<no-reply at Company.tld\>> SIZE=1364
<<< 501 5.1.7 Invalid address
501 5.6.0 Data format error

The point is that during the SMTP transaction, the application should do 
a "mail from: no-reply at company.tld" and then in the header use the 
"Company SecureFile Beta <no-reply at company.tld>" as defined by 
EmailSenderAddress variable in zendto.conf

EmailSenderAddress = 'Company SecureFile Beta <no-reply at company.tld>'
 >> Does not work

EmailSenderAddress = 'no-reply at company.tld'
 >> Works

The problem with this second option is that in the header "From:" there 
will be only the email address and not the name of the service "Company 
SecureFile Beta", so it's not a good option.

Anyone experienced this?

Thanks
tibz