Currently setting the International Sign up/Payment page is not available. You can pass the International sign up values with your payment information. Depending on the type of payment button you are using, you can use the following input types, to assist your customers with the sign up process. They will still need to click on the link to switch to the international sign up page.
<FORM ACTION="https://www.paypal.com/cgi-bin/webscr" METHOD="POST">
<INPUT TYPE="hidden" NAME="cmd" VALUE="_ext-enter">
<INPUT TYPE="hidden" NAME="redirect_cmd" VALUE="_xclick">
<INPUT TYPE="hidden" NAME="business" VALUE="YOUR EMAIL ADDRESS">
First Name
<br>
<INPUT TYPE="text" NAME="first_name" VALUE="" size="30">
<br>
<br>
Last Name
<br>
<INPUT TYPE="text" NAME="last_name" VALUE="" size="30">
<br>
<br>
Address
<br>
<INPUT TYPE="text" NAME="address1" VALUE="" size="30">
<br>
<INPUT TYPE="text" NAME="address2" VALUE="" size="30">
<br>
<br>
City
<br>
<INPUT TYPE="text" NAME="city" VALUE="" size="30">
<br>
<br>
State / Province / Region
<br>
<INPUT TYPE="text" NAME="state" VALUE="" size="30">
<br>
<br>
Zip, Postal Code
<br>
<INPUT TYPE="text" NAME="zip" VALUE="" size="15">
<br>
<br>
Country
<br>
<SELECT name="country" id="country">
<OPTION></OPTION>
<OPTION value="AI">Anguilla</OPTION>
<OPTION value="AG">Antigua</OPTION>
<OPTION value="AR">Argentina</OPTION>
<OPTION value="AU">Australia</OPTION>
<OPTION value="AT">Austria</OPTION>
<OPTION value="BE">Belgium</OPTION>
<OPTION value="BZ">Belize</OPTION>
<OPTION value="BR">Brazil</OPTION>
<OPTION value="CA">Canada</OPTION>
<OPTION value="CN">China</OPTION>
<OPTION value="CR">Costa Rica</OPTION>
<OPTION value="AN">Curacao</OPTION>
<OPTION value="DK">Denmark</OPTION>
<OPTION value="DM">Dominica</OPTION>
<OPTION value="DO">Dominican Republic</OPTION>
<OPTION value="FI">Finland</OPTION>
<OPTION value="FR">France</OPTION>
<OPTION value="DE">Germany</OPTION>
<OPTION value="GR">Greece</OPTION>
<OPTION value="GD">Grenada</OPTION>
<OPTION value="HK">Hong Kong</OPTION>
<OPTION value="IS">Iceland</OPTION>
<OPTION value="IN">India</OPTION>
<OPTION value="IE">Ireland</OPTION>
<OPTION value="IL">Israel</OPTION>
<OPTION value="IT">Italy</OPTION>
<OPTION value="JM">Jamaica</OPTION>
<OPTION value="JP">Japan</OPTION>
<OPTION value="LU">Luxembourg</OPTION>
<OPTION value="MX">Mexico</OPTION>
<OPTION value="NL">Netherlands</OPTION>
<OPTION value="NZ">New Zealand</OPTION>
<OPTION value="NI">Nicaragua</OPTION>
<OPTION value="NO">Norway</OPTION>
<OPTION value="PT">Portugal</OPTION>
<OPTION value="SG">Singapore</OPTION>
<OPTION value="ZA">South Africa</OPTION>
<OPTION value="KR">South Korea</OPTION>
<OPTION value="ES">Spain</OPTION>
<OPTION value="SE">Sweden</OPTION>
<OPTION value="CH">Switzerland</OPTION>
<OPTION value="GB">United Kingdom</OPTION>
</SELECT>
<INPUT TYPE="hidden" SELECT_NAME="country" VALUE="">
<br>
<br>
Phone Number
<br>
<INPUT TYPE="text" NAME="night_phone_a" VALUE="" size="3">
<INPUT TYPE="text" NAME="night_phone_b" VALUE="" size="15">
<br>
<br>
<INPUT TYPE="image" SRC="http://www.paypal.com/images/flag-ca.gif" BORDER="0" NAME="submit" ALT="Make payments with PayPal - it's fast, free and secure!" width="62" height="31">
</form>
Stephen Ivaskevicius
PayPal/eBay, Inc.
www.paypal.com/pdn