Relius users - beneficiary forms if a trust is named as beneficiary

The standard beneficiary instruction form says, "NOTE: if you name a trust as beneficiary, you must also provide additional information to the Administrator. The Administrator will notify you as to what additional information is needed."

The standard designation of beneficiary form itself says, "Trust beneficiary. If you name a trust as beneficiary, the trustee must satisfy additional documentation requirements no later than October 31 of the calendar year following the calendar year of your death. The Administrator will provide you or the trustee with the additional forms you must complete." (My emphasis)

Now, spousal consent, if applicable, would require an additional form. The Administrator would need a copy of the Trust.

What else might be required, other than the Trust and spousal consent mentioned above - and for RMD purposes, you have the requirements that the Trust must be irrevocable, must be valid under state law, beneficiaries must be identifiable under the trust, and Plan Administrator needs either a copy of the trust, or a certified list of beneficiaries under the trust. Do you normally direct all this to the Plan Sponsor's attorney do determine what "additional forms" might be needed, if any? I'm a little foggy here.