Percussion and bars rest problem

[Ralph Little]

Hi,
Can anybody help with this problem with percussion and bars rest?
I am trying to use the short-hand multi-voice \\ syntax and it seems to break 
after bars rest.
 
A small example:
 
\version "2.2.1"
\score {
    \drums \new DrumStaff <<
        \time 2/2
        \context DrumVoice="1"{s1*2} 
        \context DrumVoice="2"{s1*2}
        {
            bassdrum4 r4 sidestick4 r4
            R1
            r4 r8 sidestick16 ss ss8 ss4 ss8
            <<
                {hh8 hh hh hh ~ hh hh hh hh} \\
                {bd4. bd8 ss4 r8 bd8}
            >>
       }
    >>
}
 
The DrumVoices seem to disappear.
If I try to reinstate the drum voices with the 2 context definitions as at the 
start, after the bars rest, then I get a couple of empty bars because of the 
skips and the source gets really messy.
 
\version "2.2.1"
\score {
    \drums \new DrumStaff <<
        \time 2/2
        \context DrumVoice="1"{s1*2} 
        \context DrumVoice="2"{s1*2}
        {
            bassdrum4 r4 sidestick4 r4
            R1
            <<
                \context DrumVoice="1"{s1*2} 
                \context DrumVoice="2"{s1*2}
                {r4 r8 sidestick16 ss ss8 ss4 ss8}
            >>
            <<
                {hh8 hh hh hh ~ hh hh hh hh} \\
                {bd4. bd8 ss4 r8 bd8}
            >>
       }
    >>
}
 
 
I've tussled with this for some time.
Any help would be greatly appreciated!
 
Regards,
Ralph

---------
Tribal Data Solutions has moved, please visit our website for more details 
http://www.tribaldata.co.uk. 
This e-mail and any attachments are confidential and are sent on the basis of 
our copyright, e-mail and security policy which can be inspected by visiting 
http://www.tribaldata.co.uk/policies.asp.
If you are not the intended recipient, please notify the sender and delete this 
message. Thank you.
-----------