XML : XML to one level php array

I want to convert this xml output:

  <?xml version="1.0" encoding="UTF-8"?>  <directoryresponse xmlns="https://www.sisow.nl/Sisow/REST" version="1.0.0">   <directory>   <issuer>   <issuerid>01</issuerid>   <issuername>ABN Amro Bank</issuername>   </issuer>   <issuer>   <issuerid>02</issuerid>   <issuername>ASN Bank</issuername>   </issuer>   <issuer>   <issuerid>08</issuerid>   <issuername>Friesland Bank</issuername>   </issuer>   </directory>  </directoryresponse>    

to this php array:

  array(      '01' => 'ABN Amro Bank',      '02' => 'ASN Bank',      '08'=> 'Friesland Bank'    )    

I tried in many ways, but it's more difficult than I thought (for me). I hope someone can help me. Many thanks in advance!