Calculate Wald's chi-squared test to detect DIF using graded response model

[pavloviandoggy]

I am getting more into Item Response Theory for my job. I work with a lot of polytomous data, and was very excited to learn that the IRT Procedure supports the graded response model. However, I was frustrated to learn that there is no built in functionality for detecting DIF based on these analyses. I have configured my version of SAS to also support R packages, but haven't found an R package that supports Wald's chi-squared test, which is the main statistic recommended in the literature. Most information on using SAS to detect DIF also only focuses on dichotomous data and/ or non-IRT methods.

Does anyone have any idea on how I can use SAS to calculate Wald's chi-squared test? Is there a SAS macro someone could recommend? Or is there an option in the IRT Procedure that I have missed?