[NTG-context] Double integral and subscripts

Hi all, I want to typeset double integral with subscript beneath the integral symbol. I found \unic@dblint for double integral, and used the usual \limits in plain tex: \unic@dblint\limits_{\startsubstack x \ge 0,\NR 0 \le y \le T\stopsubstack} The subscript did go below the integral, but the two integral symbols are separate from each other. Any tips? Thanks a lot! Shenchen