Order Confirmation ~ Add Customer Login into Subject?

[pinksparklegirl]

Is it possible to add a customers login email address into the subject line of the confirmation email?

I'm using version 1.3.9.

The owner of the site prefers to use his own email client to organise orders rather than use Zen Cart.
Unfortunately there is no way to distinguish one email from another by looking at the "from" address, so I wondered if there is a way to add the customers login email address into the subject line along with the order number? It will have to be the login email as his site is using a mod for no account at checkout.

Thanks for any help in advance,
Sarah

[glitzsfa]

I am trying to do the exact same thing. Did you figure this out?

[pinksparklegirl]

No, I gave up as no-one replied!

[torvista]

I was looking at this last week.
Its not straightforward (I understand why), I gave up as I can't justify the time to make it work.