After Anor Londo, warp to, but do not rest, at the Sunlight Alter, when you see him there, aggro him, and Homeward Bone back to the bonfire you warped from, avoid this area now.
Go to Lost Izalith, and complete it, or mostly complete it, if you didn't know, you can open the shortcut into Lost Izalith, even if you're not a Chaos Servant, if you open it outwards (from the titanite Demon).
Once its open, go the Oswald and remove your sin, this will free Solaire from his desire to kill you, warp to outside Lost Izalith, kill all the bugs (I skipped the 9th one, until this time, just in case), and I walked through Izalith, and came back to check on him, but I suppose you may be able to quit and reload and he'd be there.
Hope his Jolly Co-operation can be helpful now!
I did try this with Reah, I killed Petrus and resolved my sin, twice! She and her servants do not forgive you.