When you create a linked server in SSMS, the System Tables are not available in the table/view listing, but they can still be accessed and queried.
To query the System Tables, you will be using the OPENQUERY call, like the example below:
SELECT * FROM OPENQUERY([Linked Server Name], ‘SELECT * FROM sys_tables’);
If you have additional questions or need any assistance, please reach out to support@cdata.com for further help