Timing Pulley Bolts, 1998, V90

[mister]

I recently changed the Timing Belt, Water Pump & two Pulleys. In attempting to remove T45 Idler Bushing bolt I snapped the tool off. The second try with a new tool resulted in rounding the shallow star bolt head. O.K., the idler arm appears to move freely but without its removal I cannot hold the bolt that secures the pulley nut. This concerns me as the movement of the belt will tend to loosen rather than tighten this nut. I've drive 600 miles so far & torque remains low at about 10 ft-lbs before the bolt & nut turn together. Can anyone provide a picture of what the head of this bolt looks like so I can make a tool to hold onto it? Is it another torx bolt or something more standard, more friendly - size?

Thanks,
Bob