Custom Model extendng another custom Type

[nowhere]

Hi all,
I have created three custom type, the last two extending the first:

<types>
           <type name="acq:docParent">
               <title>Doc father</title>
              <parent>cm:content</parent>
              <properties>
                 <property name="acq:propPadre">
                    <type>d:text</type>
                  </property>
                </properties>
           </type>

       <type name="acq:docType1">
         <title>Doc1</title>
         <parent>acq:docParent</parent>
         <properties>
            <property name="acq:propAtt1">
               <type>d:text</type>
            </property>
       </type>
 
      <type name="acq:docType2">
         <title>Doc 2</title>
         <parent>acq:docParent</parent>
         <properties>
            <property name="acq:propPass1">
               <type>d:text</type>
            </property>
       </type>
</types>

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I can create content of all three types, but If I create a docType2 content and I choose modify properties for it I don't see parent properties (acqropPadre). I was expecting this because it extends docParent. Where am I in wrong?

Hoping in some suggestion!
Greetings,
Nowhere

[nowhere]

It works if I do:

<types>
           <type name="acq:docParent">
               <title>Doc father</title>
              <parent>cm:content</parent>
               <properties>
                   <property name="acq:test">
                      <type>d:text</type>
                   </property>
              </properties>
              <mandatory-aspects>
              <aspect>acq:dataDoc</aspect>
             </mandatory-aspects>
           </type>

       <type name="acq:docType1">
         <title>Doc1</title>
         <parent>acq:docParent</parent>
         <properties>
            <property name="acq:propAtt1">
               <type>d:text</type>
            </property>
          </properties>
       </type>

      <type name="acq:docType2">
         <title>Doc 2</title>
         <parent>acq:docParent</parent>
         <properties>
            <property name="acq:propPass1">
               <type>d:text</type>
            </property>
           </properties>
       </type>
</types>

<aspects>
   <!– Aspect Dati acquisizione–>
   <aspect name="acq:dataDoc">
      <title>Data</title>
      <properties>
                 <property name="acq:propParent">
                    <type>d:text</type>
                  </property>
                </properties>
   </aspect>

  </aspects>
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If I create a docType1 content, I can see property "acqropParent" among its properties, but I can't see "acq:test". Why father type's properties are not taken by types extending it and aspect is?