How to add a custom input field on subscription buttons

[breslov]

I would like to add 2 custom input fields for my subscription buttons.  The first field(organization name) is required and the 2nd (client code) is optional.  I have found several similar solutions, but not exactly what I'm looking for because  I need a solution for both monthly and yearly subscriptions buttons.  

Also, I'm not sure how to replace the buy not button with a regular html submit button like this:

<button type="button" class="btn btn-primary">Pay Now</button>

any ideas?

Here is what I have so far...

<!-- Start of Buy Now Form -->
<form target="_self" action="https://www.paypal.com/cgi-bin/webscr" method="post">

<input type="hidden" name="cmd" value="_xclick">
<!-- Replace "business" value with your PayPal Email Address or Account ID -->
<input type="hidden" name="business" value="your email address">
<input type="hidden" name="item_name" value="Widget Statue">
<input type="hidden" name="item_number" value="WS-1001">
<input type="hidden" name="amount" value="100.00">
<input type="hidden" name="lc" value="US">
<input type="hidden" name="currency_code" value="USD">
<input type="hidden" name="no_shipping" value="2">
<!-- Replace value with the web page you want the customer to return to after a successful transaction -->
<input type="hidden" name="return" value="http://www.yourwebsite.com/ThankYou.html">
<!-- Replace value with the web page you want the customer to return to after item cancellation -->
<input type="hidden" name="cancel_return" value="http://www.yourwebsite.com/Cancel.html">

<input type="hidden" name="button_subtype" value="products">
<input type="hidden" name="no_note" value="0">
<input type="hidden" name="cn" value="Add special instructions to the seller:">
<input type="hidden" name="bn" value="PP-BuyNowBF:btn_buynow_LG.gif:NonHosted">
<!-- -->
Name Plate Engraving Information:
<br><br>

Organization Name:&nbsp;&nbsp;
<input type="hidden" name="on0" value="Organization Name">
<input type="text" name="os0" size="20">
<br><br>
Customer Code (optional):&nbsp;&nbsp;
<input type="hidden" name="on1" value="Customer Code">
<input type="text" name="os1" size="20">
<br><br>

<!-- -->
<input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_buynow_LG.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!">
<img alt="" border="0" src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif" width="1" height="1">
</form>
<!-- End of Buy Now Form -->