CIMD2 to sms-service problem with greek characters

Greetings,

Firstly, I would like to thank kannel team for the software. I use it to
connect to vodafone gr and cosmote.

The problem is that greek characters (of the messages I receive through
cimd2 (cosmote))
are not transfered correctly to the sms-service. Instead, they are replaced
by ?

My kannel.conf includes

group = smsc
smsc = cimd2
smsc-id = cosmote
host = a.b.c.d
port = X
smsc-username = USERNAME
smsc-password = PASSWORD
alt-charset = latin1
#keepalive = 5
my-number = Y

group = smsc
smsc = cimd2
smsc-id = cosmoteB
host = e.f.g.h
port = Z
smsc-username = USERNAME
smsc-password = PASSWORD
alt-charset = latin1
#keepalive = 5
my-number = Y

...

group = sms-service
keyword = default
catch-all = true
accepted-smsc = "cosmote;cosmoteB"
max-messages = 0
get-url = "
http://localhost/smsGateways/Kannel?company=COSMOTE&sender=%p&message=%a"

As far as I can see in kannel log files greek characters are received
correctly, that is _gg, _gl etc
However, examining apache access log files shows that greek character is
sent as %3F.

Thank you in advance

PS in alt-charset I have tried with no luck values 1, 2, 3 and latin1