Please provide R code which allows one to conduct a between-subjects ANOVA with -3, -1, 1, 3 contrasts. I understand there is a debate regarding the appropriate Sum of Squares (SS) type for such an analysis. However, as the default type of SS used in SAS and SPSS (Type III) is considered the standard in my area. Thus I would like the results of this analysis to match perfectly what is generated by those statistics programs. To be accepted an answer must directly call aov(), but other answers may be voted up (espeically if they are easy to understand/use).
sample.data <- data.frame(IV=rep(1:4,each=20),DV=rep(c(-3,-3,1,3),each=20)+rnorm(80))
Edit: Please note, the contrast I am requesting is not a simple linear or polynomial contrast but is a contrast derived by a theoretical prediction, i.e. the type of contrasts discussed by Rosenthal and Rosnow.