Well, after a clean install of elastix I did the following steps:
1) Under hardware detection menu it detected the cards (both ISDN and a 410 with 1 FXO and 1 FXS)
2) Changed in etc/mISDN.conf the mode of the card to from TE to NT and left it to ptmp.
3) Added the following to etc/asterisk/misdn.conf
Created SIP (200) and custom extension (201) and under custom extension in PBX the dial string is "misdn/1/201"
Nothing else. With this configuration the following things happen:
ISDN phone (201) calls SIP phone (200). Sip phone calls ISDN phone. SIP phone can get external PSTN line by pressing 9 and dials ok but the ISDN phone cannot. It says "The number you have dialed is not in service". Also when I call from ISDN phone to SIP phone there is no Call ID shown on the SIP phone but is "unknown".
I thing I've made quite a progress, I would appreciate your help on the last 2 problems.