[Xy-pic] Problem with curly arrow

[Yannis Haralambous]

Hi,

in the following formula (typeset with xy tips), the right arrow looks ugly because of the bad junction between the curly shaft and the tip. Is there some way to move the tip a bit upwards to improve this?

$$\xymatrix{  V \ar[r]^-f & W \perp H & W  \ar@{~>}[l]}.$$

Can this be done on a global level (for all ~ tips of the document)?

Thanks in advance

Yannis