LightSwitch HTML Client: How to set the value of a computed property based on another computed property -

before asking question, make simple example make question clear.

in lightswitch html client, have table 1 column: "amount"

i made computed property, "amountplustax" , set value follow,

myapp.browsetransactions.amountplustax_postrender = function (element, contentitem) {         contentitem.databind("data.amount", function () {             $(element).text(parsefloat(contentitem.data.amount) * 1.05);         });  }; 

as see, amountplustax = amount * 1.05

the problem have want make computed property value depends on value of "amountplustax" computed property. like, amountplustaxplusinterest = amountplustax * 1.03

how possible?

this doesn't work:

myapp.browsetransactions.amountplustaxplusinterest_postrender = function (element, contentitem) {     $(element).text(parsefloat(contentitem.screen.amountplustax) * 1.03); }; 

although doesn't directly answer question, alternatively capture inserting/inserted/updating/updated events in dataservice , update 1 or both of fields instead of using computed properties.

for example:

partial void sometable_updating(sometable entity)     {         if (entity.somefield.isnullorwhitespace())             entity.somefield = utils.converttovalidname(entity.name);     }