Sort Custom UIList markers

Question

a little question about UI list, i'm trying to make a custom marker panel. It's aim is to recense all markers on timeline. Then i have a custom operator to jump to these markers. I managed to call the UIlist, but i want it to be sorted by frame number (the marker at the frame number 1 being automatically above marker at frame number 2) and i have no clue to do that. For now i just managed to display frames number for more clearity... Here's my piece of code so far :

import bpy
from bpy.props import IntProperty, CollectionProperty , StringProperty 
from bpy.types import Panel, UIList
import os


# custom list
class Markers_items(UIList):

    def draw_item(self, context, layout, data, item, icon, active_data, active_propname, index):
        split = layout.split(0.8)
        layout.prop(item, "name", text="", icon='MARKER',  emboss=False, translate=True)
        split.label("%d" % (bpy.context.scene.timeline_markers[index].frame))

    def invoke(self, context, event):
        pass   

# draw the panel
class MarkerListPanel(Panel):
    """Creates a Panel in the Object properties window"""
    bl_space_type = 'FILE_BROWSER'
    bl_region_type = 'TOOLS'
    bl_category = "Editing Tools"
    bl_label = "Markers List"

    def draw(self, context):
        layout = self.layout
        scn = bpy.context.scene

        rows = 2
        row = layout.row(align=False)
        row.template_list("Markers_items", "", scn, "timeline_markers", scn, "marker_index", rows=rows)


def register():
    bpy.utils.register_module(__name__)
    bpy.types.Scene.marker_index = IntProperty()


def unregister():
    bpy.utils.unregister_module(__name__)
    del bpy.types.Scene.marker_index

if __name__ == "__main__":
    register()

I don't have a clue about that... Any help ? Thanks in advance to all ! :D