Thanks in advance, if any one may help me.

In dynamics ax 2009 we were having 3 financial dimensions i.e. Dept, CostCenter and Purpose. Here in AX 2012, we may use any number of dimensions.

Where i am struck is, i have created a new form. Now i want to show a interface to user where he may select the three dimensions i.e. Dept, Cost Center and Purpose, by selecting values of drop down.??

In Ax 2009 we use to create a Relation on Extended Data Type. and by putting name of this Extended Data Type in the window of field where we want to show the DropDown.  For example(in ax 2009), in order to show Financial Dimensions upon my customized or newly created form i use to put the Extended Data Type 'Dimension' in the Properties window of Table's Field, where i have to provide selection of Dimensions to user.

How to Acheieve this in Dynamics Ax 2012?

How to provide a drop-down to user for which data is form some other table.?