DigiSign 
Description
Add a digital signature to the pdf
Definition
 Function DigiSign(DestFileName as string,
                   ImgFileName as string,
                   Name as string,
                   Reason as string,
                   Location as string,
                   ContactInfo as string,
                   Certificate as string,
                   Password as string,
                   Left as Integer,
                   Top as Integer,
                   Width as integer,
                   Height as Integer) as Integer
Parameters
 DestFileName  : The destination pdf filename
 ImgFileName   : The image filaname to draw as signature
 Name          : The signer name
 Reason        : The signing reason
 Location      : The Signing Location
 ContactInfo   : The signer conatact information
 Certificate   : The certificate filename
 Password      : The pasword for the certificate
 Left          : The left position for the signature
 Top           : The Top position for the signature
 Width         : The Width for the signature
 Height        : The Height for the signature
Returns
 0  The document is signed 
 1  DestFileName omitted
 2  Certificate filename omitted
 3  Certificate file does no exists
 4  Invalid pasword
 5  No private key in the certificate
 6  Unkown error
Notes :
 This function sign the loaded pdf and if the process is complete, create the DestFileName pdf file and remove the document form memory
 The signature Image is any valid image file accepted by AddImageFromFile function, the white color is set to transparent
 These parameters can be left to blanck
   Name
   Reason
   Location
   ContactInfo
 The Certicate can be obtain from the window certifate store by exportation, note that you must use the option export the private key
 The certicate Password is the one used when exporting the certificate
 If With or Height is set to zéro, a blanck signature is added to the document
 You can co-sign the document as well