Abominations were with rules starting 2nd Edition!
The 2nd Edition Players Guide contained the actual abomination rules on 3 pages.1 After it each of the Breedbooks (and Hengeyokai) did always included abomination rules for the Fera and how they turn undead (or not).
It is notable, that in the 1st Edition Players Guide, abomination rules are absent despite including a reference to the fresh 2nd Edition of Vampire combat rules.2
In Revised, again, there are rules, this time in the Storyteller Handbook.3. Players Guide to Changing Breeds did not mention them at all.
Also of note: Book of Wyrm in 1st and 2nd Edition doesn't mention them.
If you want to read the original draft of the rules - which differs from the players' guide that would be copied over to revised, you'd look at the March 1993 Crossover Book "Under a Blood Red Moon".4 The Werewolf Players Guide came out 2 months later, with quite deep alterations to the rules: Ego took the axe and instead the PG brought very explicit rules about what the Abomination can and can't do and in general... the rules in Under a Blood Red Moon appear like a first draft.
1 - Werewolf Players Guide, 2nd Edition, Clarkston (2000), pp.190: Vampiric Wolves.
2 - Werewolf Players Guide, 1st Edition, Stone Mountain (1993).
3 - Werewolf Storyteller Handbook, Revised Edition, Clarkston (2002), p. 197.
4 - Under a Blood Red Moon, 2nd Edition, Stone Mountain (1993), p.94.