David,
Without digging into this too much..
Are you talking about the symbology once it gets over to your mobile device, or is the same issue present in ArcPad on your desktop?
As far as your SDE symbols not appearing in ArcPad (on your mobile device), it's probably just a lack of the specific font file on the mobile device. Via the symbol selector in ArcMap, determine which font file (like esri_220.ttf) the symbol uses.
Open the symbol selector > Edit symbol > On the Character Marker tab you will see the font that's being used.
Copy that font from the C:\Windows\Fonts folder and paste it into the fonts folder on your mobile device ...\Windows\Fonts.
Most of the issues I've seen related to symbology becoming random symbols (like #, !, $, etc) is due to a missing font file on the mobile device.
If you try this and don't seen any different, reply with a little more info and we can go from there.