Hello People, Does anyone know how to create a button with only two corners being rounded?

I can get it to work in all clients, except Outlook. I need to know how to code the arcsize for a corner. Any thoughts?

Thanks
Here is my code:


    <tr><!--======= button 200W ======-->
<td align="center">
<table width="590"  border="0" cellpadding="0" cellspacing="0"  align="center" class="main">
<tr>
<td width="5">&nbsp;</td>
<td align="left" valign="top" style="padding:10px 0px 10px 0px; ">
<div align="center">
<!--[if mso]>
<v:roundrect xmlns:v="urn:schemas-microsoft-com:vml" xmlns:w="urn:schemas-microsoft-com:office:word" href="#" style="height:40px;v-text-anchor:middle;width:190px;" arcsize="25%" stroke="f" fillcolor="#42DD4B">
    <w:anchorlock/>
    <center style="color:#ffffff;font-family:sans-serif;font-size:16px;font-weight:bold;">
  Learn More
    </center>
  </v:roundrect>
  <![endif]-->
<![if !mso]>
<table cellspacing="0" cellpadding="0" align="center"> <tr> 
<td align="center" width="190" height="40" bgcolor="#42DD4B" 
style="-webkit-border-bottom-left-radius: 15px; -moz-border-bottom-left-radius: 15px; border-bottom-left-radius: 15px; -webkit-border-top-right-radius: 15px; -moz-border-top-right-radius: 15px; border-top-right-radius: 15px; color: #ffffff; display: block;">
<a href="#" target="_blank" style="font-size:16px; font-family:sans-serif; text-decoration: none; line-height:40px; width:100%; display:inline-block">
<span style="color: #ffffff; font-size:16px; font-family:sans-serif; line-height:40px;">
<b>Learn More</b></span></a>
</td> 
</tr>
</table> 
<![endif]>
</div>
</td>
<td width="5">&nbsp;</td>
</tr>
</table></td><!--End--></tr>