There are 2 ways to do this:
1. You could do it the proper way and record each trustee as owning shares.
We have written an article on how pensions (e.g. SIPPs and SSASes) should be recorded as shareholders:
Exactly the same principle applies to EBTs. You can record up to 10 trustees as joint shareholders. To create a joint shareholder see below:
How do I create a joint shareholder?
2. You could simply register the name of the EBT as a corporate shareholder. When asked for the company number, just enter '00000000' or 'n/a' Please see How Do I Allot Shares to a Corporate?