[HELP] Samsung PBX with Asterisk

I am fairly new to the pbx side of voip and have setup with some success a pbx at our work (AAH 1.03)

However I do have the following problems and I am wondering if somebody can help.

The digium cards connect to another standard pbx (Samsung in this case) which provides one branch connectivity to the main pbx.

The digium fxo ports is seen as zap/1 + zap/2 +zap/3.

I have a problem with either the sipura units or the pbx. I am not sure yet.
After pressing 0 you get a line on the main pbx. Now you can dial either an extension or in the case I am battling with, get an outside line from telco by pressing *xxxx (pin code) and then a 0 for the telco line. However, after getting the approval tone from the samsung pbx, if you press 0 nothing happens. My sipura units is setup with dial plan (*xx|x.) with is suppose to mean I can dial everything.

I would really appreciate if somebody can help or even just point my in the right direction.