Eugene,
When I try to create a DataSet with some new fields (and no High and Low), the DataSet gets distorted, containing the High and Low values, and with the Low ptice higher then the Open price.
I hope you can help me,
Thanks

Dan,

You can help yourself by reading the Bars object chapter of the WealthScript Programming Guide. The inherent feature of a Bars object, it says, is representing a historical series of OHLC/V data. They must be present in a Bars object. The capability of supporting Named DataSeries (such as open interest or non-adjusted price) is optional.

Based on previous experience I'd suggest you start your question with why (you want to do that something) rather than how (to make Wealth-Lab do it). So, why are you getting rid of High and Low?

Also, are you using an in-house developed provider or our ASCII provider for that purpose? If the latter then tell us how are you defining the fields.