use color font in emailbody sending smartform

Hello,

I am sending smartform output by email as an PDF.
That part is going okay.
the email is programmed.

I fill the emailbody in ABAP coding
with statements like:

objtxt = 'Dear Sir, Madam, <BR>'.

APPENDobjtxt.

objtxt = '<B><U>Thank you for your order:</U></B> <BR>'.

APPENDobjtxt.

i use these commands

<BR> carriage return

<B> Bold

<U> Underline.

that objtxt is used in function

* Sending the document

     CALL FUNCTION 'SO_NEW_DOCUMENT_ATT_SEND_API1'

       EXPORTING

         document_data              = doc_chng

       TABLES

         packing_list               = objpack

         object_header              = objhead

         contents_bin               = lt_pdf[]

         contents_txt               = objtxt

         receivers                  = reclist

Now i have to print some (not all) text in the email body in color green.
Does anyone knows how to achieve this.

Regards