Spot genes are recessive, so you need to have some color on the dam's side as well in order to get color out of any sire. You can make white faces and such out of Angus cows or other females that don't have recessive spot genes, but don't expect loud spotted calves out of cows like that, no matter what you breed em to.
If your SimAngus cows have some color on the Simmental side--i.e. a spot gene, a white or blaze face, or white legs--you could get color out of those bulls. And if these females are actually baldies or have white feet or bellies, you're a lot more likely to get more chrome.
There are some dominant genes that make color out of solid cows--the white or roan gene in Shorthorn will share dominance, and a white face like in Hereford is dominant...you get the white face every time. Matings to solid colored cattle (like Angus) can produce calves with goggle eyes or brockled face markings...those face markings are on the solid animal's side and can only be expressed in conjunction with the white face. Just keep in mind that crossbred cattle that are heterozygous for dominant traits will only pass the gene on to 50% of their offspring, so a white faced bull that has one solid parent won't throw all white faced calves.