The way i read this is you are asking if you can use X-ships in OP while you are playing the EAW campaigns which have been ported over to OP.
If this is the case I'll bet you have patched to the latest patch on OP and are selecting Advanced era right??
There is a problem with advanced era not being represented in the latest patch
It's an easy fix really. You have to go to the OP directoryu and go into the Metaassets\Serverprofiles folder and edit the Time.gf file. it'll be set to read only so you'll have to change the properties of the file so you can edit it with notepad.
All you have to do is add in one line.
In yours you'll find this table at the bottom of the file:
[Clock/StartingDate]
BaseYear = 2263
0 = 0
1 = 10
2 = 20
you need to add in a line like this:
3 = 30
this will allow for the start time of the advanced era. Save the file and then you'll have to start a new game but ut should allow yoou to get X-Ships now.
Of course if this isn't your problem then I've typed a lot of junk for nothing.