If you have defined a data table and want to copy that definition to another space you can do this using the following steps:
Create a new process in the space with the data table
Create an activity on the level 1 diagram
Attach the data table to the activity
Copy the process to the space that you want the data table in. This will also copy the definition to the new space. Note: if the data table already exists in the new space it will not copy it again so long as the definition has not been changed in either space.
Delete the process in both spaces