Hello
I was also told it is limited to 40 and it is so with SAP.
I agree that it is a pain to have two different systems linked but with different constrained.
If SAP is feeding PDMLink then the limit is not a problem. If you have PDMLink feeding SAP then it is a problem.
I do not know if you can constrain PDMLink to only have 40 characters.
Best of luck.
NacNac