Custom View not appearing

Here is the XML for the layout in which I want my custom view to appear.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:rs="http://schemas.android.com/apk/res/com.bookcessed.booksearch"
    android:id="@+id/widget273"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <TextView
        android:id="@+id/csp_tv_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Choose Your Source"
        android:textSize="40sp"
        android:textColor="#ffc83200"
        android:gravity="center"
        android:paddingTop="15dip"
        android:paddingBottom="75dip"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" />

    <com.bookcessed.booksearch.SearchProviderButton
        android:id="@+id/csp_spb_1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_below="@+id/csp_tv_title"
        rs:providerName="BOOKP" />

</RelativeLayout>

Here is the custom view's XML:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:rs="http://schemas.android.com/apk/res/com.bookcessed.booksearch"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" >

    <RelativeLayout
        android:id="@+id/pv_rl_strings"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:layout_alignParentTop="true" >

        <TextView
            android:id="@+id/pv_tv_search"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Search"