I'm having trouble configuring a custom decimal precision for a UoM.

Here's the scenario:

My company sells spices and manufactures blends. We would like our inventory quantities to be weight in pounds with a decimal precision of at least 6 (Ex: Oregano qty: 0.029999 lbs). But the "rounding precision" in the UoM I defined only allows up to 3 digits after the decimal point (0.000). So, when I set the inventory for Oregano, OpenERP rounds it to .030000. The same goes for items I add in a Bill of Materials.

These are all the rounding and precision settings that I've been able to find and change:

Settings->Warehouse->Decimal precision on weight = 6

Settings->Database Structure->Decimal Accuracy->Product Unit of Measure = 6

Settings->Database Structure->Decimal Accuracy->Stock Weight = 6

Warehouse->Unites of Measure->lbs

Unit of Measure: lbs
Category: Weight
Type: Reference Unit of Measure for this Category
Rounding Precision: 0.000 <-- OpenERP will not allow more than 3 digits after the decimal.

Any ideas how to allow quantities with 6 decimal places?

Thanks!