Center elements of HorizontalScrollView when not enough to make it scroll

I have a Layout with a HorizontalScrollView containing a LinearLayout for a Menu where the contents are inflated with the contents of the DB. This works fine however when there are not enough elements to make the HSV scroll this does not fill the width of the screen which ideally should be centered. i.e. Currently:

| Element 1 Element 2                         | <- edge of screen

Instead of:

|        Element 1            Element 2       | <- edge of screen

whilst still being able to:

| Element 1 Element 2 Element 3 Element 4 Elem| <- edge of screen now scrolling

The layout XML is:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/mainLinearLayout"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <TextView 
         android:id="@+id/header"
         android:layout_width="fill_parent"
         android:layout_height="25dp" >
    </TextView>

    <ScrollView
         android:id="@+id/scroll1"
         android:layout_width="fill_parent"
         android:layout_height="fill_parent"
         android:layout_weight="1" >

        <LinearLayout
             android:id="@+id/contentLayout"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:orientation="vertical" >

        </LinearLayout>
    </ScrollView>

    <HorizontalScrollView
        android:id="@+id/horizontalScrollView1"
        android:layout_width="fill_parent"
        android:layout_height="30dp">

        <LinearLayout
            android:id="@+id/footerLayout"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            an