1. Create a class (MyLookup) which inherits SysLookup and override the lookupDimension() method with the following code.
public static lookupDimension(FormStringControl _stringControl, Name _dimensionName) { SysLookup::lookupDimension(_stringControl, _dimensionName); }
2. Override the lookup method of the formcontrol.
public void lookup() { MyLookup::lookupDimension(this, 'CostCenter'); }