Hi,
To do that you need to create an enhancement point in the webdynpro.
Try this:
- Go to the webdynpro and create an enhancement point
- Go to component controller to the context, node COMP_CONTEXT, subnode ACCOUNTING and add the attributes refering your custom fields, do it with right click "Create using wizard" -> "Attributes from component structure". Select your custom field and push Ok.
- Go to the view you want (I guess V_DO_ACCOUNT_DETAIL) update the mapping in context. Create a new node and an attribute to store the description/s.
- Go to the layout and add a new Label you don't need to fill the property "text". Set the property "Layout data" to "MatrixHeadData"
- Create a transparent container below the label.
- Within the container add an input field , create the binding of property "value" with the attribute context.
- Change the property of the label "label for" to refer the input field.
- Create in the container a textview and do the binding with the attribute you created to store the descriptions. Change the property "Visible" of this textview defining a binding with "Bind to the property of selected Attibute" and select the input field. In this way when the input field is hide the text view is also hide.
- To fill the descriptions you need to add a post-exit in a method, for example in method WDDOMODIFYVIEW.
And that's all. The configuration you did in SPRO is still working, so if you have some dynamic class and method to hide the field in some conditions is still working...
If you want to do some special alignment in all the custom fields may be you need to add all of them in the webdynpro... 
Hope this help you.
Regards.