Modifying BAB with a Template

[Haligon]

I've been kludging together modifiers to simulate the Fused Eidolon feature of my Synthesist Summoner, and I think I've gotten everything covered except for BAB.

Does anyone know the coding to modify BAB (preferably within a Template, but Spell Adjustment would also work). I can modify the BAB progression, but really, all I want to do is add a +1 to BAB itself at this point (I'll juggle that in the .user file as level changes)

FWIW, this is what I'm doing now for the other mods (in case anyone else is looking to deal with Synthesists in HeroLab):
-Created a 'Fused with Eidolon' Acquired Template that includes STR/DEX/CON/Natural Armor bonuses.
-Added claw attacks to the Template (though they appear as secondary attacks...not sure how to fix that)
-Added cAnimEvas and cAnimDevo abilities the Template to grant the Devotion and Evasion modifiers to the Synthesist
-Added Spell Adjustments for Darkvision and (multiple) False Life entries (for the Temp HP)
-Added various 'Other Adjustments' to deal with the abilities granted by Evolutions.
-Added a +5 to hit Adjustment for the Claw Attack, and a +3 Damage Adjustment for the Claw Attack (to remove the 'secondary attack' penalties)

At this point, I add the template, Activate the Fused Eidolon Ability (which takes care of Save Bonuses and Shield Bonus to AC, but nothing else), and turn on all of the other adjustments in the Adjust Tab, and I'm functional , with the exception that my BAB is off by 1. Any assistance in this part would be appreciated (I'll be consolidating as many parts of the adjustments into the Template as possible later on)