Area spells and range bonuses

[rsarres]

How do you apply range bonuses to area spells without being affected to the spell itself?
For example, a cold ball I has an area of effect of 20' radius and +35 range bonus 0' - 10'.  Range is defined as distance from the caster to the target.
So, to get a +35 EAR range bonus, the caster must be at least 10' away from the target and the caster will be affected by the cold ball damage, as the radius of the spell is 20´.

We thougt about casting the ball 15´ away from the target, so the target will still be on the area of effect AND 10´ from the caster, but the caster will be outside of the area of effect. Something like this:

center of the area spell --------15´-------- target --10´-- caster
           *------- area of effect (20' radius) -------|

However, it sounded unrealistic, as the center of the area spell is the worst place to be (+20 EAR). So why one side of the explosion would deliver more damage?

Another idea was to make the caster immune to his own area spells. It would result in overpowered area spells.

Any suggestions?

[netbat]

The range bonus is based on the distance from the caster to the center/target of the AOE spell, supposedly because it is harder to place the centerpoint exactly where you want it the further away you are trying to hit. So yes, if you want to get that point blank bonus, you have to wait till your target is closer than 10' and you are also going to be in the AOE. IF you don't want to be hit by your own spell and don't want any minuses, target something between 20' and 50' away or learn spell mastery to change the shape of the AOE(if your GM allows it).

[rsarres]

Thanks!