Now that is really strange I'm afraid I can't help - I myself started with EB 1.2

But just one note: why are you sure he is using BI. There are roxolani units in EB:

https://www.europabarbarorum.com/fac...tae_units.html

Rauxsa-alanna Baexdzhyntae (Roxolani Riders)
Rauxsa-alanna Uaezdaettae (Roxolani Noble Cavalry)

Although I have no idea how they got to Rome....