JMP and estimates of values below the limit of detection

Hej all.

I am new here and unfortunatelly also new in statistic (and JMP).

As my project for master thesis I am working with one data set, environmental data set.

I have some less than values and I have to replace them with something.

I did not want to take the easiest way and take just half, more I had in mind MLE or something. But I do not know how to do it in JMP.

Does anybody know how to do that? What do you usually do with values below the limit of detection?

Best regards.