I finally managed to have working at the same time:
+ Google Talk with video chat
+ Added Market + auto market update working
+ Contacts and Calendar sync (There is no Accounts menu in System Settings. Once the Google Account is added, you can ajust the Sync configuration on the Contacts / Calendar apps. )
To get that you have to:
0) Set USB Debugging on and unknown sources in System Settings
1) Get Root. To do so you have to options:
1.a) Using SuperOneClick
1.b) Using Update.zip ( CWM Recovery) and su-126.96.36.199-efgh-signed.zip
2) Install Ghost Commander (getting and using the file com.ghostsq.commander.apk)
3) Ghost Commander -> application -> settings ->Root mode on leaving /sdcard
4) Copy the attached files to the sdcard
5) Navigate to /system and then click on "Remount /system"
6) Compare the files with the ones you have in /system. Copy the missing ones.
7) Make a settings->privacy->factory reset
Here you can find the working /system files from a Coby Kyros MID1125 4G Android Tablet: