Subscription with multiple domains + php mail

[Eric1]

Hi all,

I have a problem with the plesk subscription + php mail.

In plesk i have a subscription called e-schildkamp.nl
under that subscription i have multiple domains like:
e-schildkamp.nl (linked to the subscription)
bouwbedrijfnobel.nl
oosterbouw.nl
eschildkamp.nl

Its all works fine except if i use PHP mail on one of the domains.

for example:
i send a PHP mail script from oosterbouw.nl to erc1986@gmail.com i receive the mail in my spambox (of gmail).
the mail is not coming from oosterbouw.nl no its comes from e-schildkamp.nl (linked to the subscription)

My question is simple, how can this be solved?
Is the only solution to this problem that i should create a new subscription for each new domain i added into plesk12?


I hope that its all clear for you readers.
And thanks for helping me out.

Gr. Eric

CentOS 6.6 + plesk 12