Tree Example (replace the "yourdomain.com" with your actual domain).  
This example will work if you have Miva Merchant with a single storefront in 
the domain.  Also, you need to make sure there are no / characters in the 
category name if you are going to display it in the url like these links below.

<mvt:if expr="g.Category_Code">
<mvt:foreach iterator="child1" array="category_level1">
 <br>
 <mvt:if expr="l.settings:child1:code EQ g.Category_Code">
  <mvt:if expr="NOT ISNULL l.settings:child1:tree_image">
   <img src="&mvt:child1:tree_image;" border="0">
  <mvt:else />
   &mvt:child1:name;
  </mvt:if>
 <mvt:else />
  <mvt:if expr="NOT ISNULL l.settings:child1:tree_image">
   <a href="http://www.yourdomain.com/c/&mvta:child1:code;/&mvta:child1:name;.html">
<img src="&mvt:child1:tree_image;" border="0"></a>
  <mvt:else />
   <a href="http://www.yourdomain.com/c/&mvta:child1:code;/&mvta:child1:name;.html">
<u>&mvt:child1:name;</u></a>
  </mvt:if>
 </mvt:if>
 <mvt:if expr="'|'$l.settings:child1:code$'|' CIN g.category_level_branch">
  <mvt:foreach iterator="child2" array="category_level2">
   <br>
   &nbsp;&nbsp;
   <mvt:if expr="l.settings:child2:code EQ g.Category_Code">
    <mvt:if expr="NOT ISNULL l.settings:child2:tree_image">
     <img src="&mvt:child2:tree_image;" border="0">
    <mvt:else />
     &mvt:child2:name;
    </mvt:if>
   <mvt:else />
    <mvt:if expr="NOT ISNULL l.settings:child2:tree_image">
     <a href="http://www.yourdomain.com/c/&mvta:child2:code;/&mvta:child2:name;.html">
<img src="&mvt:child2:tree_image;" border="0"></a>
    <mvt:else />
     <a href="http://www.yourdomain.com/c/&mvta:child2:code;/&mvta:child2:name;.html">
<u>&mvt:child2:name;</u></a>
    </mvt:if>
   </mvt:if>
   <mvt:if expr="'|'$l.settings:child2:code$'|' CIN g.category_level_branch">
    <mvt:foreach iterator="child3" array="category_level3">
     <br>
     &nbsp;&nbsp;&nbsp;&nbsp;
     <mvt:if expr="l.settings:child3:code EQ g.Category_Code">
      <mvt:if expr="NOT ISNULL l.settings:child3:tree_image">
       <img src="&mvt:child3:tree_image;" border="0">
      <mvt:else />
       &mvt:child3:name;
      </mvt:if>
     <mvt:else />
      <mvt:if expr="NOT ISNULL l.settings:child3:tree_image">
       <a href="http://www.yourdomain.com/c/&mvta:child3:code;/&mvta:child3:name;.html">
<img src="&mvt:child3:tree_image;" border="0"></a>
      <mvt:else />
       <a href="http://www.yourdomain.com/c/&mvta:child3:code;/&mvta:child3:name;.html">
<u>&mvt:child3:name;</u></a>
      </mvt:if>
     </mvt:if>
     <mvt:if expr="'|'$l.settings:child3:code$'|' CIN g.category_level_branch">
      <mvt:foreach iterator="child4" array="category_level4">
       <br>
       &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
       <mvt:if expr="l.settings:child4:code EQ g.Category_Code">
        <mvt:if expr="NOT ISNULL l.settings:child4:tree_image">
         <img src="&mvt:child4:tree_image;" border="0">
        <mvt:else />
         &mvt:child4:name;
        </mvt:if>
       <mvt:else />
        <mvt:if expr="NOT ISNULL l.settings:child4:tree_image">
         <a href="http://www.yourdomain.com/c/&mvta:child4:code;/&mvta:child4:name;.html">
<img src="&mvt:child4:tree_image;" border="0"></a>
        <mvt:else />
         <a href="http://www.yourdomain.com/c/&mvta:child4:code;/&mvta:child4:name;.html">
<u>&mvt:child4:name;</u></a>
         </mvt:if>
       </mvt:if>
      </mvt:foreach>
     </mvt:if>
    </mvt:foreach>
   </mvt:if>
  </mvt:foreach>
 </mvt:if>
</mvt:foreach>
<mvt:else />
 <mvt:foreach iterator="parent" array="parents">
  <br>
  <mvt:if expr="NOT ISNULL l.settings:parent:tree_image">
   <a href="http://www.yourdomain.com/c/&mvta:parent:code;/&mvta:parent:name;.html">
<img src="&mvt:parent:tree_image;" border="0"></a>
  <mvt:else />
   <a href="http://www.yourdomain.com/c/&mvta:parent:code;/&mvta:parent:name;.html">
<u>&mvt:parent:name;</u></a>
  </mvt:if>
 </mvt:foreach>
</mvt:if>






.htaccess file example (replace the "yourcode" with your store's code)

RewriteEngine On
RewriteCond %{REQUEST_URI} ^/p/(.*)/(.*)	[NC]
RewriteRule (.*) /mm5/merchant.mvc?Screen=PROD&Product_Code=%1&Category_Code=&Store_Code=yourcode [R,L]
RewriteCond %{REQUEST_URI} ^/pc/(.*)/(.*)/(.*)	[NC]
RewriteRule (.*) /mm5/merchant.mvc?Screen=PROD&Product_Code=%1&Category_Code=%2&Store_Code=yourcode [R,L]
RewriteCond %{REQUEST_URI} ^/c/(.*)/(.*)	[NC]
RewriteRule (.*) /mm5/merchant.mvc?Screen=CTGY&Category_Code=%1&Store_Code=yourcode [R,L]