I'm trying to build application that use single config passed by server as non native JSON (can contain functions). Everything works fine so far but I'm curious why PagingToolbar does not have an option to use parent Grid store?

I have tried to set store in my config like this, but without success:

{...
   store:Ext.StoreMgr.lookup('unique_store_id')
}

Is there any way to do so without writing tons of javascript for each view defining store, grid and other items in my application or at least extend functionality of PaginationToolbar that use options from parent object?

UPDATED, Here is short example of server response (minified)

{
"xtype":"viewport",
"layout":"border",
"renderTo":Ext.getBody(),
"autoShow":true,
"id":"mainFrame",
"defaults":{"split":true,"useSplitTips":true},
"items":[
	{"region":"center",
	"xtype":"panel",
	"layout":"fit",
	"id":"content-area",
	"items":{
		"id":"manager-panel",
		"region":"center",
		"xtype":"tabpanel",
		"activeItem":0,
		"items":[
			{
				"xtype":"grid",
				"id":"domain-grid",
				"title":"Manage Domains",
				"store":{
					"xtype":"arraystore",
					"id":"domain-store",
					"fields":[...],
					"autoLoad":{"params":{"controller":"domain","view":"store"}},
					"url":"index.php"
				},
				"tbar":[...],
				"bbar":{
					"xtype":"paging",
					"id":"domain-paging-toolbar",
					"store":Ext.StoreMgr.lookup('domain-store')
				},
				"columns":[...],
				"selModel":new Ext.grid.RowSelectionModel({singleSelect:true}),
				"stripeRows":true,
				"height":350,
				"loadMask":true,
				"listeners":{
					"cellclick":activateDisabledButtons
				}
			}
		]
	},
}
]
}