TickSpec: How do I use the same step name in different features?

I am fiddling around with the Gilded Rose kata in F#. I am writing my tests in TickSpec and FsUnit so that they essentially mirror Jim Weirich's Gilded Rose tests written in RSpec.

When I run them in Visual Studio's Test Explorer, I get the following error:

Ambiguous step definition
(AgedBrieSpecs.I update the quality|NormalItemSpecs.I update the quality)
on line 5 in Feature: Aged Brie quality updates  
    "When I update the quality"

Basically, I'm trying to use the same function name in different features. But they are in different modules. I could even put them in different namespaces, but that doesn't help either.

So then, how do I use step names that happen to be the same, but in different features? Am I just "doing it wrong"?

My feature text and counterpart F# code is as follows:

NormalItemFeature.txt:

Feature: Normal item quality updates

Scenario 1: Each day the sell-in value decreases by one
    Given a normal item with a sell-in value of 10
    When I update the quality
    Then its sell-in value should be 9

AgedBrieFeature.txt:

Feature: Aged Brie quality updates

Scenario 1: Each day the sell-in value decreases by one
    Given Aged Brie with a sell-in value of 10
    When I update the quality
    Then its sell-in value should be 9

NormalItemSpec.fs:

module GildedRoseCsSpecs.NormalItemSpecs

open FsUnit
open TickSpec
open System.Linq
open GildedRoseCs

let mutable rose = GildedRose([].ToList())
let item = Item(Name = "Normal Item", SellIn = 10, Quality = 5)

let [<Given>] ``a normal item with a sell-in value of (\d+)`` (sellIn : int) =
    item.SellIn <- sellIn

let [<When>] ``I update the quality`` () =
    rose <- GildedRose([item].ToList())
    rose.UpdateQuality()

let [<Then>] ``its sell-in value should be (\d+)`` (sellIn : int) =
    rose.Items.First().SellIn |> should equal sellIn

AgedBrieSpecs.fs:

module GildedRoseCsSpecs.AgedBrieSpecs

open FsUnit
open TickSpec
open System.Linq
open GildedRoseCs

let mutable rose = GildedRose([].ToList())
let item = Item(Name = "Aged Brie", SellIn = 10, Quality = 5)

let [<Given>] ``Aged Brie with a sell-in value of (\d+)`` (sellIn : int) =
    item.SellIn <- sellIn

let [<When>] ``I update the quality`` () =
    rose <- GildedRose([item].ToList())
    rose.UpdateQuality()

let [<Then>] ``its sell-in value should be (\d+)`` (sellIn : int) =
    rose.Items.First().SellIn |> should equal sellIn

And finally, I have the following lines in my Fixtures.fs file:

// FeatureFixture definition omitted for brevity

type NormalItemFeature () = inherit FeatureFixture("NormalItemFeature.txt")
type AgedBrieFeature () = inherit FeatureFixture("AgedBrieFeature.txt")

P.S. Yes, I understand that there is a lot of duplication here that could be consolidated. While this is a contrived example, I can imagine that two entirely different features could have steps with the same descriptive text. It seems to me that TickSpec ought to be able to handle such name collisions.